From GMod Wiki
(Redirected from Convar)
What is a ConVar?
"The console provides a command-line interface for the advanced configuration of Source games.
Just about any configuration task can be completed from the console, and in fact many have to be.
Entered commands come in two forms: commands and variables. Commands are simply keywords,
but variables ("CVars" or "ConVars") require a value of some sort before they are accepted.
When a ConVar is given a value it will store that value."
- Valve Wiki
You can set convars using RunConsoleCommand, and get convars using GetConVar. You can create them using CreateConVar or CreateClientConVar