arm glove; arm warmer
A tubular garment worn on the forearm, often knitted, for warmth or fashion. Similar to a fingerless glove but without hand coverage.
On cold days, I wear arm warmers while working on the computer.
She gave me hand-knitted arm warmers as a present.
Compound of 腕 (ude, 'arm') and 袋 (fukuro, 'bag'), literally 'arm bag'. The reading ふくろ becomes ぶくろ due to rendaku.