muscle, tendon / vein, artery / reason, logic / plot, storyline / counter for long thin things; counter for roads or blocks when giving directions / lineage, descent

Counter for long, thin things.

(anatomy) a sternocleidomastoid muscle

(Internet slang) Short for 胸が熱くなる.

a badge, an insignia worn on the chest

(anatomy, uncommon, dated) cephalothorax

full breasts / boob job, breast augmentation surgery

(figuratively, idiomatic) heart pounding; butterflies in one's stomach

(idiomatic) a more powerful person partners with a less powerful person, such as for practicing

(idiomatic) to be unsettled, to be uneasy