Being over and above what is necessary, or what must be used or reserved; not wanted, or not used; superfluous; as, I have no spare time.
Held in reserve, to be used in an emergency; as, a spare anchor; a spare bed or room.
Every checker added to a point already occupied with two checkers.
an extra component of a machine or other apparatus
an extra car wheel and tire for a four-wheel vehicle
more than is needed, desired, or required; "trying to lose excess weight"; "found some extra change lying on the dresser"; "yet another book on heraldry might be thought redundant"; "skills made redundant by technological advance"; "sleeping in the spare room"; "supernumerary ornamentation"; "it was supererogatory of her to gloat"; "delete superfluous (or unnecessary) words"; "extra ribs as well as other supernumerary internal parts"; "surplus cheese distributed to the needy"
kept in reserve especially for emergency use; "a reserve supply of food"; "a spare tire"; "spare parts"
An extra man on a made point - it can be moved and the point will still be safe.
An extra checker on a point that may be used for hitting or making a point without leaving behind a blot.
A specification when ordering a switchboard. An extra protection device is bolted in place and connected to the bus. For future service expansion, all the customer has to do is connect a branch circuit to it.
A checker in excess of two on a point. It is a spare because it can be moved without giving up the point.
A connector point reserved for options, specials, or other configurations. The point is identified by an (E#) for location on the electrical schematic.
An extra checker on a made point which can be moved without endangering the point.