Handcuff n. : A fastening, consisting of an iron ring around the wrist, usually connected by a chain with one on the other wrist; a manacle; -- usually in the plural.

Handcuff v. t. : To apply handcuffs to; to manacle.

Example:
What are the dimensions of a Handcuff key?

Taxonomy
handcuffs, cuffs, wrists, restraints, locks, the cuffs, handcuffed, Double locks, small hands, chain, hinged handcuffs, lock spring, suspect, police officers, Hiatt Handcuffs, leg irons, Police handcuffs, Police restraints.

Defination from the web:
handcuff, has a metal block or bar between the cuffs. ... Stan Willis' Guinness World Record Handcuff Collection. Collection of modern and historical restraints from the Czech Republic ...