the chunk of parent
the descriptor of parent
the function-name of argument
the property-name of object
The of keyword is used in several places to describe child-parent relationships between objects and arguments to function calls.
It is used in chunk expressions: char 32 of steve
It is used in descriptors for child objects: file "doc.xnd" of folder "Documentation"
It is used in function calls: the sqrt of sixteen
It is used in property descriptors: the location of myRectangle
It is used in operators: steve is an element of bill
It is used in certain control structures: repeat for each myElement of myList
The in and of keywords are synonyms practically everywhere in both XION and HyperTalk, even when it would otherwise make no sense (e.g., the sqrt in 4 or "e" is of "hello").