PIE*ghebhのフォークから。 語源的にはjavelinと同じ。 フォークに似ていることから名付けられた。
Possibly the primitive meaning of the words may have been 'top', 'vertex'; this may have given rise to the sense of 'gable', and this latter to the sense of 'fork', a gable being originally formed by two pieces of timber crossed at the top supporting the end of the roof-tree." [OED]Related: Gabled; gables; gable-end.