出典:Wiktionary
From French billard, originally referring to the wooden cue stick, diminutive of Old French bille (“log, tree trunk”), from Vulgar Latin *bilia, probably of Gaulish origin (compare Old Irish bile (“large tree, tree trunk”)), from Proto-Celtic *belyos (“tree”), from Proto-Indo-European *bʰolh₃yos (“leaf”), from *bʰleh₃- (“blossom, flower”).
From French billiard, equivalent to bi- (“two”) + -illiard.