腹筋 (はらすじ)sit-up; abdominal muscles; abs

sit-upnoun (common) (futsuumeishi), noun or participle which takes the aux. verb suru
abdominal muscles; absnoun (common) (futsuumeishi), noun or participle which takes the aux. verb suru

腹筋, its kanji, and other words that share them.Open this graph

Kanji in 腹筋

腹はらabdomen; belly
裏腹うらはらopposite; reverse
下っ腹したっぱらabdomen; stomach
腹部ふくぶabdomen
太っ腹ふとっぱらgenerous; magnanimous
腹痛ふくつうstomach ache; abdominal pain
腹心ふくしんone's confidant; trusted friend
中腹ちゅうふくhalfway up (down) a mountain; mountainside
筋すじmuscle; tendon
筋肉きんにくmuscle
大筋おおすじoutline; summary
道筋みちすじpath; route
心筋しんきんheart muscle; myocardium
消息筋しょうそくすじinformed circles
鉄筋てっきんrebar; (iron) reinforcing bar
一筋ひとすじone long straight object (e.g. strand of hair, beam of light, wisp of smoke)

See how 腹筋 connects to the rest of Japanese.