The Collaborative International Dictionary of English v.0.48:

handlock \handlock\ n.
   a metal loop that can be locked around the wrist, usually
   used in pairs; a handcuff.

   Syn: handcuffs, handcuff, cuffs, cuff, manacle.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

handlock
    n 1: shackle that consists of a metal loop that can be locked
         around the wrist; usually used in pairs [syn: handcuff,
         cuff, handlock, manacle]