The Collaborative International Dictionary of English v.0.48:

Interlock \In`ter*lock"\, v. i.
   To unite, embrace, communicate with, or flow into, one
   another; to be connected in one system; to lock into one
   another; to interlace firmly.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Interlock \In`ter*lock"\, v. t.
   1. To unite by locking or linking together; to secure in
      place by mutual fastening.
      [1913 Webster]

            My lady with her fingers interlocked. --Tennyson.
      [1913 Webster]

   2. To connect together so that the parts work together as a
      coordinated unit; to connect as a single system.
      [PJC]

WordNet (r) 3.0 (2006):

interlock
    n 1: a device that prevents an automotive engine from starting;
         "car theives know how to bypass the ignition interlock"
         [syn: interlock, ignition interlock]
    2: the act of interlocking or meshing; "an interlocking of arms
       by the police held the crowd in check" [syn: mesh,
       meshing, interlock, interlocking]
    v 1: coordinate in such a way that all parts work together
         effectively [syn: interlock, mesh]
    2: hold in a locking position; "He locked his hands around her
       neck" [syn: lock, interlock, interlace]
    3: become engaged or intermeshed with one another; "They were
       locked in embrace" [syn: interlock, lock]