buttocks; bottom; butt
thigh; part of a whole; portion of a sum; (stock) share; strand of a thread; low-level administrative unit, translated as "section" or "department" etc, ranked below 科; classifier for long winding things like ropes, rivers etc; classifier for smoke, smells etc: thread, puff, whiff; classifier for bands of people, gangs etc; classifier for sudden forceful actions
Practice each character