/bel"free/ , n. , pl. belfries .
1. a bell tower, either attached to a church or other building or standing apart.
2. the part of a steeple or other structure in which a bell is hung.
3. a frame of timberwork that holds or encloses a bell.
4. Slang. head; mind: a belfry full of curious notions.
5. have bats in one's belfry . See bat 2 (def. 3).
[ 1225-75; ME belfray, appar. b. earlier berfray ( belfredus, dissimilated var. of berefredus ber ( c ) frit, equiv. to berc defense, protection, refuge (c. OE gebeorg; see HARBOR) + frit peace, (place of) safety (c. OE frith ) ]