Ping: Also known as latency. Ping is the reaction time of your internet connection. Reaction means how quickly your device gets a response after sending a request. A fast(low) ping means a good flexible connection. Ping is measured in milliseconds (ms). 0-50ms ping is the standard for very good connection.

Jitter: Also known as Packet Delay Variation (PDV), jitter is the measurement of variability in ping. Jitter is not usually noticeable when browsing light website, but when you streaming and gaming a high jitter can cause buffering and interruptions. The acceptable jitter number is upto 100ms.

Download Speed: Download speed is how much data you can pull from a server on the internet to your device per second.

Upload Speed: Your upload speed is how much data you can send from your device to the internet or server per second.

That is all the most important terms to know.

There are few websites to test your connection speed. Before checking your speed, close all the running apps which uses data to get the most accurate result.

www.speedtest.net is the most popular website to check your connection. But they will ask you to stop Ad Block on their website to use their service.

There is www.fast.com for this service too. You can use that without any ad. I like their service most.

There is view other option too. Check those below link to use them.

https://www.centurylink.com/home/help/internet/internet-speed-test.html

https://www.spectrum.com/internet/speed-test.html