Definition of pigeonhole:
(n) :
one of an array of
compartments for sorting post, messages etc. at an office, or college (for example); a hole, or roosting place for
pigeons
"fred was disappointed at the lack of post in his pigeonhole."
(v) :
to
categorize; especially to limit or be limited to a particular category,
role, etc
"fred was tired of being pigeonholed as a computer geek."