腋: armpit; axil

腋 yè

noun
: support by the arm; to help; to promote; at the side

腋 | わき waki

noun
: armpit; under one’s arm; side; flank
: beside; close to; near; by
: aside; to the side; away; out of the way
: off-track; off-topic
: deuteragonist; supporting role
: (Abbreviation) second verse (in a linked series of poems)

腋下 ye4xia4: underarm; armpit [えきか ekika]

腋毛 ye4mao2: armpit hair [わきげ wakige: underarm hair]

腋窩[窝] ye4wo1: armpit [腋窩 | えきか ekika]

腋生 ye4sheng1: axillary (botany); budding in the angle between branch and stem
[えきせい ekisei: axillary growth]

腋臭 ye4chou4: body odor; bromhidrosis; armpit odor; underarm stink
[わきが wakiga: body odor]

肘腋 zhou3ye4: lit. armpit; elbow and armpit; fig. right up close (to a disaster); in one’s backyard; on one’s doorstep

葉[叶]腋 ye4ye4: axil [葉腋 | ようえき youeki: leaf axil]

Japanese common word / expression
腋明け | わきあけ wakiake
: robe worn by military officials with a round collar, unstitched open sides, and no wrapped fabric along the bottom
: small opening in the side of traditional Japanese clothing (where the sleeve meets the bodice, below the armpit); clothing with such an opening (usu. worn by women or children)

千金の裘は一狐の腋に非ず | せんきんのきゅうはいっこのえきにあらず senkin no kyuu wa ikko no eki ni arazu
: an expensive fur coat will not be made with a single fox alone; to rule a country requires many great men

Chinese idiom
變生肘腋 [变生肘腋] bian4 sheng1 zhou3ye4
: lit. calamity in one’s armpit; a major coup happening on one’s doorstep; trouble or danger in one’s own backyard

集腋成裘 ji2 ye4 cheng2 qiu2
: many hairs make a fur coat; many small contributions add up to something big; many a mickle makes a muckle