1630s, "to be locked together," from inter- "between" + lock (v.). Related: Interlocked; interlocking. As a noun, attested by 1856.
car theives know how to bypass the ignition interlock
an interlocking of arms by the police held the crowd in check
interleaf
interleague
interline
interlinear
interlingual
interlock
interlocution
interlocutor
interlope
interloper
interlude
