A colon (':') is placed after an identifier, or list of identifiers, for associating names with some entities, as follows. It occurs in declarations of objects, or components of objects such as records and protected objects. Similarly, a colon is to be found after the names of subprogram parameters and after the names of generic formal objects.
A colon is also used after an identifier when declaring/renaming an exception, or when declaring an exception choice parameter. Also, it can be used when specifying a loop or block name.