1. a passkey with much of the bit filed away so that it can open different locks;
The Collaborative International Dictionary of English v.0.48:
Skeleton \Skel"e*ton\, a.
Consisting of, or resembling, a skeleton; consisting merely
of the framework or outlines; having only certain leading
features of anything; as, a skeleton sermon; a skeleton
Skeleton bill, a bill or draft made out in blank as to the
amount or payee, but signed by the acceptor. [Eng.]
Skeleton key, a key with nearly the whole substance of the
web filed away, to adapt it to avoid the wards of a lock;
a master key; -- used for opening locks to which it has
not been especially fitted.
Skeleton leaf, a leaf from which the pulpy part has been
removed by chemical means, the fibrous part alone
Skeleton proof, a proof of a print or engraving, with the
inscription outlined in hair strokes only, such proofs
being taken before the engraving is finished.
Skeleton regiment, a regiment which has its complement of
officers, but in which there are few enlisted men.
Skeleton shrimp (Zool.), a small crustacean of the genus
Caprella. See Illust. under Laemodipoda.
WordNet (r) 3.0 (2006):
n 1: a passkey with much of the bit filed away so that it can
open different locks