/un bohlt"/ , v.t.
1. to open (a door, window, etc.) by or as if by removing a bolt; unlock; unfasten.
2. to release, as by the removal of threaded bolts: He unscrewed the nuts and unbolted the inspection cover.
v.i.
3. to become unbolted or unfastened.
[ 1425-75; late ME; see UN- 2 + BOLT 1 ]