Terminology
This page lists the main terms you may need while playing on the server.
Technical terms
TPS
TPS (Ticks Per Second) — the number of ticks per second.
It’s similar to FPS (Frames Per Second) — the number of frames per second, but on the server side.
The normal and maximum TPS on the server is 20.
If TPS drops below 10, the game may become noticeably worse.
Source — minecraft.wiki
Chunk
A chunk is a 16x16 block area of the world with unlimited height that the server loads into memory.
Learn more on minecraft.wiki