The white ball in billiards or pool that a player strikes with a cue stick to hit other balls.
From 'cue' (from French 'queue' meaning tail, because the stick resembled a tail) plus 'ball'. The term emerged in the 19th century as billiards became a popular game.
The cueball is the only ball a player can legally hit with their stick, making it the gateway to all other shots—without it, every other ball on the table is unreachable, which is why accidentally sinking it is called a 'scratch' and costs you the turn.
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