A primitive is a word that is defined by the system. For example, + is a primitive. The meaning of a primitive is fixed and cannot be changed.
A primitive is spelled with a graphic character (such as +) or with a graphic modified by an inflection (a dot or colon), as in +. or +: .
A primitive is also spelled by one or more letters followed by a dot or colon. For example, i. is a primitive that is called index or index of depending on how it is used.