File:Callback icon.png

A callback is a type of member that allows the user to pass a piece of code (as a function) to be called internally by the software later on. Note that a callback is not a method, despite sharing a similar icon. Just like Method, Property, and Event, a Callback is a member type of its own (ie: [[MemberName (Callback)]]).

Usage:

Object.Callback = function()
-- put stuff here
end

print(Object.Callback) -- errors; may only be written to.