Here’s what’s being measured:
Download - The rate in MBit/s that data is transferred from the Internet to your computer.
Upload - The rate in MBit/s when data is being transferred from your computer to the Internet.
Latency - The time it takes for one signal to travel electronically from a website i.e server to your computer after you request it. It’s not the download speed, but instead the measure of how long it takes for the download to begin once your device makes the information request.
Ping - A ping is a signal sent to a host that requests a response. It serves two primary purposes, to check if the host is available and to measure how long the response takes.
Jitter - Technically, is a variance in latency, or the time delay between when a signal is transmitted and when it is received. This variance is measured and is described as the disruption in the normal sequence of sending data packets.