The expression language is used to define dynamic values for component properties and expression tags. Expressions often involve one or more other values that are used to calculate a final value. Expressions don't do anything, other than return a value.
For an overview and syntax of the expression language, see Expression Language Overview and Syntax.
In this section, we cover all of the built in expression functions available inside Ignition. Each page will have a banner at the top that looks like this:
This lets you know that you are looking at a function for the expression language.