Intramural (adjective)
Within the walls; within one institution, particularly a school.
“Intramural sports involve teams that are all within the same school.”
Intramural (adjective)
Within the substance of the walls of an organ.
“intramural pregnancy”
Intramural (noun)
A (usually sports) competition between teams belonging to the same school.
Intermural (adjective)
Between walls; enclosed by walls.
Wiktionary