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Internet glossary
Ping, latency, jitter, bandwidth… internet words can be confusing. This glossary explains 48 common terms in plain, everyday language, with simple examples. No technical background needed.
Internet basics
The building blocks. Start here if you are new to how the internet works.
Internet
A worldwide network of computers that can send information to each other.
The internet links billions of devices: phones, laptops, servers, TVs and more. When you open a website, your device asks another computer (a server) for the page, and the server sends it back in small pieces.
Your home connects to the internet through an internet service provider, usually over fibre, cable, a phone line or a mobile network.
Example: Think of the internet as a huge road network, and the information you send as parcels travelling along it.
ISP (Internet Service Provider)
Also called: Internet provider, Broadband provider
The company that connects your home or phone to the internet.
Your ISP provides the line or mobile signal that links you to the wider internet. You usually pay them a monthly fee for a plan with a certain speed and sometimes a data limit.
Not every slow connection is the ISP’s fault. Wi-Fi problems, old devices and busy home networks are very common causes too.
Speed test
Also called: Internet speed test, Broadband speed test
A quick check that measures how fast data moves to and from your device.
A speed test sends test data between your device and a test server and times it. Most speed tests show download speed, upload speed and ping.
A speed test is a snapshot: it shows how your connection performed at that moment, on that route, to that server.
Internet health check
A test that looks beyond speed to check how responsive and stable your connection is.
A high speed number alone does not guarantee a good experience. An internet health check also measures ping, jitter and how much delay appears when the connection is busy.
Hyndr combines these into one easy score and explains what each part means for everyday activities like video calls, gaming and streaming.
Online and offline
Online means connected to the internet. Offline means not connected.
A device can be connected to Wi-Fi but still be offline if the router itself has lost its internet connection. That is why your phone may show full Wi-Fi bars but nothing loads.
Speed and data
How much data your connection can move, and how that is measured.
Bandwidth
The maximum amount of data your connection can carry at once.
Bandwidth is the size of the pipe. A bigger pipe lets more data flow at the same time, which helps when many people or devices are online together.
Bandwidth is about capacity, not responsiveness. A connection can have lots of bandwidth and still feel laggy if its ping or jitter is high.
Example: A motorway with 6 lanes has more bandwidth than a single-lane road. More cars fit, but each car does not drive faster.
Throughput
The amount of data that actually gets through your connection in practice.
Bandwidth is the maximum. Throughput is what you really get after Wi-Fi, other devices, distance and busy networks take their share.
The speed you see in a speed test is a measure of throughput.
Example: Bandwidth is how many lanes a road has. Throughput is how many cars actually got through in an hour.
Download speed
Also called: Downstream
How fast data comes from the internet to your device.
Download speed affects loading websites, streaming video, downloading files and installing updates. It is measured in megabits per second (Mbps).
Most home activities use far more download than upload, which is why internet plans usually advertise download speed first.
What is good? Rough guide for one person: 5 Mbps for HD video, 25 Mbps for 4K video, more when several people share the connection.
Upload speed
Also called: Upstream
How fast data goes from your device to the internet.
Upload speed matters when you send things: your camera and voice in a video call, posting photos, live streaming, sending large email attachments and backing up files to the cloud.
Many connections have much lower upload than download speed. A weak upload is a common reason video calls freeze even when Netflix works fine.
What is good? Rough guide: 3 Mbps or more for a smooth HD video call; 10 Mbps or more for live streaming.
Mbps (megabits per second)
Also called: Megabits per second, Mb/s, Gbps, Kbps
The unit used to measure internet speed: millions of bits sent each second.
A bit is the smallest piece of digital data, a single 1 or 0. One megabit is one million bits. 1,000 Mbps is 1 Gbps (gigabit per second); 1 Mbps is 1,000 Kbps (kilobits per second).
Internet speeds use bits, but file sizes usually use bytes. One byte is 8 bits. So Mbps (small b) and MB/s (capital B) are different units.
Example: On a 100 Mbps connection, a 100 MB file takes about 8 seconds, not 1 second, because 100 MB is 800 megabits.
Megabit vs megabyte (Mb vs MB)
Also called: Mbps vs MBps, Bits vs bytes
A megabyte (MB) is 8 times bigger than a megabit (Mb).
Internet speeds are measured in megabits per second (Mbps). Downloads, file sizes and data allowances are usually shown in megabytes (MB) or gigabytes (GB).
To turn Mbps into MB per second, divide by 8. A 40 Mbps connection can download about 5 MB per second.
Plan speed ("up to" speed)
Also called: Advertised speed, Subscribed speed
The maximum speed your internet plan promises, not a speed you will always get.
Plans are usually sold as "up to" a speed, such as "up to 100 Mbps". Real results are often lower because of Wi-Fi, device limits, busy times and the route your data takes.
To compare a result with your plan fairly, test on a device connected by an Ethernet cable with other devices paused.
Data usage and data cap
Also called: Data limit, Data allowance, FUP (Fair Usage Policy)
How much data you have used, and the limit your plan may set on it.
Every video, download and web page uses data, measured in megabytes (MB) or gigabytes (GB). Some plans, especially mobile plans, include a monthly or daily limit called a data cap.
When you go past the cap, your provider may slow your connection (often called a Fair Usage Policy) or charge extra. Speed tests use data too, so mobile users should keep an eye on their allowance.
What is good? A full Hyndr Health Check uses up to 200 MB, and often less.
Ping, latency and jitter
How quickly and how steadily your connection responds. This matters most for games and calls.
Latency
Also called: Delay, Response time, Lag
The time it takes for data to travel from your device to a server and back.
Latency is a delay, measured in milliseconds (ms). Lower is better. It decides how quickly things react when you click, speak or press a button in a game.
Latency depends on distance, the route your data takes, your Wi-Fi and how busy the network is. Speed and latency are different: a fast connection can still have high latency.
Example: Speed is how many people a bus can carry. Latency is how long the bus takes to make the trip.
What is good? Rough guide: under 20 ms is excellent, 20–60 ms is good, 60–100 ms is fine for most things, and above 100 ms can make games and calls feel slow.
Ping
Also called: Ping time, Round-trip time (RTT)
A quick “are you there?” message used to measure latency.
Ping sends a tiny message to a server and measures how long the reply takes. The result, in milliseconds, is often just called “your ping”. People use the words ping and latency almost interchangeably.
Gamers care about ping because it is the delay between pressing a button and the game server seeing it.
Example: Like shouting “hello” across a valley and timing how long the echo takes to come back.
What is good? For online gaming, under 50 ms is good and under 20 ms is excellent.
Jitter
Also called: Latency variation, Ping variation
How much your ping changes from moment to moment.
If your ping goes 20 ms, 21 ms, 20 ms, your jitter is low and your connection feels steady. If it goes 20 ms, 90 ms, 35 ms, your jitter is high and things feel choppy.
High jitter causes robotic voices on calls, frozen video and sudden lag spikes in games, even if the average ping looks fine. Wi-Fi interference and busy networks are common causes.
Example: Jitter is like a bus that usually takes 20 minutes but sometimes takes 5 and sometimes 60. The average looks fine, but you never know when it will arrive.
What is good? Rough guide: under 5 ms is excellent, under 20 ms is fine, above 30 ms often causes problems.
Loaded latency
Also called: Latency under load, Working latency, Responsiveness
Your ping while the connection is busy downloading or uploading.
Ping is often measured when the connection is quiet (idle latency). But real life is busy: someone streams, a phone backs up photos, a game updates. Loaded latency measures how much extra delay appears when the connection is working hard.
A big jump between idle and loaded latency is a sign of bufferbloat, and it explains why calls break up when someone else in the house starts a download.
Example: Idle ping 18 ms, ping during upload 82 ms. The connection added 64 ms of delay under load.
What is good? Less than 25 ms of added delay is good. More than 100 ms is often noticeable.
Idle latency
Also called: Unloaded latency, Idle ping
Your ping when the connection is quiet and nothing else is using it.
Idle latency is the best-case delay of your connection. Most simple speed tests only show this number. Compare it with loaded latency to see how well your connection copes when it gets busy.
Bufferbloat
Extra delay caused when network equipment queues up too much data.
Routers and modems hold data in a waiting area called a buffer. When the buffer is too big and the connection is busy, data waits in a long queue. Everything, including your game or call, gets stuck behind it.
Bufferbloat shows up as high loaded latency. Some routers have a setting called SQM or QoS that can reduce it.
Example: Like a supermarket with one long queue: even if you only have one item, you wait behind everyone with a full trolley.
Milliseconds (ms)
One thousandth of a second, the unit used for ping, latency and jitter.
1,000 milliseconds make one second. A blink of an eye takes roughly 100–150 ms. For internet responsiveness, smaller numbers are better.
Lag
Also called: Lag spike
An everyday word for a noticeable delay in a game, call or app.
Lag is what you feel when latency is high or jitter is unstable. A lag spike is a sudden short burst of delay. Lag is usually caused by latency, jitter or packet loss rather than low download speed.
Reliability and stability
Whether your data arrives safely and your connection stays steady.
Packet
Also called: Data packet
A small piece of data. Everything online is sent as packets.
Files, videos and messages are cut into thousands of small packets. Each packet travels across the internet separately and is put back together at the other end.
Example: Like posting a big jigsaw puzzle as many small envelopes that are reassembled on arrival.
Packet loss
When some pieces of data never arrive at their destination.
When packets go missing, they must be sent again or skipped. You may see freezing video, words dropping out of calls or characters jumping around in games.
Common causes are weak Wi-Fi, faulty cables and overloaded networks. Web browsers cannot always measure true packet loss, so any browser-based figure is an estimate.
What is good? 0% is ideal. Even 1–2% can be noticeable in games and calls.
Connection stability
Also called: Stable connection, Network reliability
How steady and consistent your connection stays over time.
A stable connection keeps similar speed and ping without sudden drops, spikes or disconnections. Stability often matters more than raw speed for video calls, online classes and gaming.
Low jitter, low packet loss and a small difference between idle and loaded latency are all signs of a stable connection.
Network congestion
Slowdown that happens when too much data tries to use the same network at once.
Congestion can happen inside your home (many devices on one Wi-Fi) or further away (many people in your area online at once). It lowers speed and raises ping and jitter.
Example: Like a road during rush hour: the road is the same, but there are too many cars.
Peak hours
Also called: Busy hours, Prime time
The busiest times of day for internet use, usually evenings.
Between roughly 7 pm and 11 pm many people stream, game and browse at once, so networks can become congested. Testing at different times helps show whether a slowdown is linked to busy hours.
Timeout
When a request takes too long and the device stops waiting for a reply.
If a server does not answer within a set time, the request "times out". Occasional timeouts are normal; frequent ones suggest an unstable connection, a blocked route or a busy server.
Throttling
Also called: Bandwidth throttling, Speed throttling
When a provider deliberately slows your connection down.
A provider may slow your connection after you pass a data limit, during busy times, or for certain types of traffic. Your plan terms usually explain when this can happen.
One slow result does not prove throttling. Repeated tests at different times, ideally over Ethernet, give much stronger evidence.
Wi-Fi and home network
The equipment and signals inside your home that connect your devices.
Router
Also called: Wi-Fi router, Home gateway
The box that shares your internet connection with all the devices in your home.
The router creates your home network and Wi-Fi, and directs traffic between your devices and the internet. Many providers supply a single box that is both a modem and a router.
Restarting the router, placing it in an open central spot and keeping its software updated can often improve a slow connection.
Modem
Also called: ONT (fibre), ONU
The device that connects your home to your provider’s line.
The modem translates the signal on your provider’s line (fibre, cable or phone line) into data your router can use. On fibre connections this box may be called an ONT or ONU.
Example: The modem is the front door to the internet. The router is the hallway that leads to each room.
Wi-Fi
Also called: Wireless network, WLAN
A wireless way to connect devices to your router using radio signals.
Wi-Fi is convenient, but its signal weakens with distance and walls, and it can be disturbed by neighbouring networks and household devices. That means Wi-Fi often adds delay and lowers speed compared with a cable.
Wi-Fi only connects you to your router. Full Wi-Fi bars do not guarantee the internet itself is working well.
2.4 GHz, 5 GHz and 6 GHz Wi-Fi
Also called: Wi-Fi bands, Dual-band, Tri-band
Different radio frequencies that Wi-Fi can use, each with its own strengths.
2.4 GHz reaches further and passes through walls better, but it is slower and more crowded. 5 GHz is faster with less interference but has a shorter range. 6 GHz (Wi-Fi 6E and Wi-Fi 7) is faster still, with the shortest range.
If you are close to the router, 5 GHz or 6 GHz usually gives better speed and lower jitter.
Example: 2.4 GHz is like a loud low voice that carries through walls; 5 GHz is clearer but only heard in the same room.
Signal strength
Also called: Wi-Fi signal, RSSI, dBm
How strong the Wi-Fi or mobile signal is where your device is.
Weak signal means lower speed, more delay and more lost data. Signal strength is often shown as bars, or technically in dBm, where a number closer to zero (like -50 dBm) is stronger than -80 dBm.
Interference
Other signals or objects that disturb your Wi-Fi.
Neighbouring Wi-Fi networks, microwave ovens, cordless phones, Bluetooth devices, thick walls, mirrors and water tanks can all weaken or disrupt Wi-Fi. Interference often shows up as high jitter and packet loss.
Ethernet
Also called: Wired connection, LAN cable, Network cable
A cable that connects a device directly to your router.
An Ethernet cable avoids Wi-Fi problems such as distance, walls and interference. It usually gives the fastest, steadiest connection, which is why it is best for gaming, important calls and accurate speed tests.
Mesh Wi-Fi
Also called: Mesh network, Wi-Fi extender, Repeater
Several Wi-Fi units working together to cover a larger home.
A mesh system places small units around the home so every room gets a good signal. A Wi-Fi extender (repeater) is a simpler, cheaper option that rebroadcasts the signal, though it can add some delay.
LAN and WAN
Also called: Local area network, Wide area network, Home network
LAN is your home network. WAN is the wider network outside it.
Your LAN (local area network) includes everything connected to your router. The WAN (wide area network) is the connection from your router out to your provider and the internet. Problems can sit on either side.
QoS (Quality of Service)
Also called: SQM, Traffic priority
A router setting that decides which traffic goes first when the connection is busy.
QoS lets a router prioritise time-sensitive traffic such as calls and games over big downloads. A related feature, SQM (smart queue management), can greatly reduce bufferbloat. Change these settings only if you are comfortable doing so.
Behind the scenes
The systems that quietly route your data around the world.
Server
A computer that stores and sends websites, videos, games and other data.
When you watch a video or load a page, a server somewhere sends the data to you. Servers live in data centres all over the world. The further away the server is, the longer data usually takes to arrive.
Test server
Also called: Measurement server, Speed test server
The server a speed test talks to while it measures your connection.
A speed test measures the path between your device and its test server. A server that is far away or busy can make results look worse. Hyndr picks the server that responds fastest, which is not always the nearest city.
Route and hops
Also called: Network path, Hop, Traceroute
The path your data takes across the internet, made of many steps called hops.
Data rarely travels in a straight line. It passes through many routers (hops) owned by different networks. A longer or busier route adds latency. A tool called traceroute can show each hop along the way.
Example: Like a train journey with several stations. Each stop adds a little time.
IP address
Also called: IPv4, IPv6, Public IP, Private IP
A number that identifies a device or network on the internet, like a postal address.
Every connected device needs an address so data knows where to go. Your router has a public IP address that the internet sees, and gives each device at home a private IP address. IPv4 addresses look like 203.0.113.5; newer IPv6 addresses are much longer.
DNS (Domain Name System)
Also called: DNS server, DNS lookup
The internet’s phone book. It turns website names into IP addresses.
When you type a website name, your device asks a DNS server for that site’s IP address. A slow or failing DNS server can make websites slow to start loading even when your speed is good.
Example: You remember a friend’s name; your phone looks up their number. DNS does the same for websites.
CDN (Content Delivery Network)
A network of servers that keeps copies of content close to users.
Big websites and streaming services store copies of their content in many cities. You are served from a nearby copy, which reduces latency and speeds up loading.
VPN (Virtual Private Network)
A service that sends your traffic through an encrypted tunnel to another server.
A VPN can add privacy, but it also adds an extra stop on your data’s journey, so speed tests through a VPN often show lower speed and higher ping. Turn a VPN off when you want to test your real connection.
Fibre, cable and DSL broadband
Also called: FTTH, Fiber, Optical fibre, Cable internet, DSL, ADSL
The main types of wired internet connection to a home.
Fibre sends data as light through glass strands and usually offers the highest speeds and lowest latency. Cable uses TV-style coaxial cable. DSL uses old telephone lines and is usually slower, especially far from the exchange.
Mobile data (4G and 5G)
Also called: Cellular data, LTE, 5G, Hotspot
Internet delivered over a mobile phone network instead of a cable.
4G and 5G connect through nearby mobile towers. Speed and ping depend on signal strength, how many people use the same tower, and whether you are indoors or moving. Results can change a lot within minutes.
Mobile data usually has a data cap, so large tests and downloads count towards your allowance.
TCP and UDP
Also called: Protocol, Transmission Control Protocol, User Datagram Protocol
Two common sets of rules for sending data across the internet.
TCP checks that every packet arrives and resends anything missing. It is reliable, so it is used for web pages, email and downloads. UDP sends data quickly without checking. It is used for live calls and games, where a late packet is no longer useful.
Example: TCP is a tracked courier that needs a signature. UDP is shouting across a room: fast, but some words may be missed.