A
gib is a colloquial term for a chunk of
flesh, usually one that has recently been liberated from its owner by
explosive force. The noun later became a
verb when
Quake and its sequels (and, for a time, pretty much every subsequent
first person shooter) allowed players to get blown into chunky
salsa pieces.
The term was coined almost accidentally when one of the artists working on Doom named the graphic files of some sprites of dismembered chunks as 'GIBn', short for 'Giblets'. The term was first used in the playable portion of a game in Rise of the Triad (which included a mode called 'Ludicrous Gibs'). In Id Software games from Doom onwards, killing an enemy or character with a blow that is sufficiently greater in damage points than the target's health results in them exploding into gibs. Gibbing can therefore be executed with any weapon that can strike a powerful enough single blow (therefore if the Quad Damage power-up is collected, even the weakest of weapons may be able to gib someone).
Although Doom's gibs were limited to a fixed sequence of two dimensional frames for each enemy, Quake made the individual pieces out of polygons that trailed particles of blood as they tumbled through the air (often with a unique piece for the head, complete with surprised expression). Quake 2 added the effect of the gibs being blown in the direction away from the explosion. Quake III Arena included recognisable gibs for most body parts, including a seperate skull, ribcage, brain and jawbone.
'Gib' is officially pronounced with a hard 'G' as in 'giraffe', although occasionally it is heard spoken with a soft 'G' as in Maurice Gibb, due to the speaker having learnt of the term from reading it online.
Saving Private Ryan contains a good gibbing during a climactic scene.