large wooden mallet; maul
A heavy wooden hammer used in carpentry, timber framing, or driving stakes.
大工が掛け矢で杭を打ち込んでいる。
The carpenter is driving a stake with a large mallet.
Standard spelling with okurigana, making the reading clear.
Alternate spelling without okurigana; also common.
Compound of 掛け (kake, 'hanging' or 'hooking') + 矢 (ya, 'arrow'), but the exact derivation is uncertain. The spelling is conventionally associated with the tool.