Slang for a nickname, pseudonym, alias or username. For example, a Twitter handle is how people identify themselves on Twitter. For decades, "CB handles" have been the short but unique identities truck drivers use over citizens band radio (see CB radio
A temporary name or number assigned to a file, font or other object. Also called a "file descriptor," an operating system may assign a sequential number to each file that it opens as a way of identifying and keeping track of it. At the processing level, applications activate open, close, read and write operations by file handle rather than file name.
In a drawing program, a handle is a tiny, square block on an image that can be grabbed for reshaping.
The handles are the tiny (blue) squares that are displayed when an object is selected.