Returns from a subroutine, eval, do FILE, sort block or regex eval block (but not a grep or map block) with the value given in EXPR. Evaluation of EXPR may be in list, scalar, or void context, depending on how the return value will be used, and the context may vary from one execution to the next (see wantarray). If no EXPR is given, returns an empty list in list context, the undefined value in scalar context, and (of course) nothing at all in void context.
(In the absence of an explicit return, a subroutine, eval, or do FILE automatically returns the value of the last expression evaluated.)
Unlike most named operators, this is also exempt from the looks-like-a-function rule, so return ("foo")."bar" will cause "bar" to be part of the argument to return.