MDBG Mobile Chinese English Dictionary (iPhone, Android, Windows Phone)

膝盖	xī gài	knee / (Internet slang) to kneel down (in admiration)
小腿	xiǎo tuǐ	lower leg (from knee to ankle) / shank
跪倒	guì dǎo	to kneel down / to sink to one's knees / to grovel
蜷伏	quán fú	to curl up / to lie with knees drawn up / to huddle up
膝下	xī xià	at the knee (in reference to children) / (salutation used in letters to parents or grandparents)
发软	fā ruǎn	to weaken / to go soft (at the knees)
卑躬屈膝	bēi gōng qū xī	to bow and bend the knee (idiom); fawning / bending and scraping to curry favor
护膝	hù xī	kneepad / knee brace
袚	fú	knee-pads / buskins
拜倒	bài dǎo	to prostrate oneself / to fall on one's knees / to grovel
下跪	xià guì	to kneel / to go down on one's knees
促膝	cù xī	to sit knee to knee
膝	xī	knee
奴颜婢膝	nú yán bì xī	servile and bending the knee (idiom); fawning / bending and scraping to curry favor
腘	guó	knee pit / popliteal fossa (medicine)
骹	qiāo	shank (the leg from knee to ankle) / leg (from hip to ankle) / (horse anatomy) pastern
长揖	cháng yī	to bow deeply, starting upright with arms straight out in front, one hand cupped in the other, then moving the hands down to one's knees as one bows, keeping the arms straight (a form of greeting)
齐膝	qí xī	level with one's knees / knee-length (skirt etc) / knee-deep (mud etc)
腘窝	guó wō	popliteal (anatomy) / hollow at the back of the knee
绕膝	rào xī	(children) run around parent's knees / fig. to stay to look after one's elderly parents