A condition body is the main part of a trigger condition. It describes explicitly the object that a condition is related to, for example a channel or a selection. All further parts of the condition determine the properties or parameters of this object.
A condition starts with a condition body. It goes after the AND/OR operator that connects two or more conditions together. You can choose a condition body value from the drop-down list:
Condition body options can be divided into several groups based on the type of object they refer to. For a quick hint on a particular option take a look at the area coloured in yellow.