上下

shàng xiàshangxia

1. the top and bottom of sth
2. the full vertical extent of sth; from top to bottom
3. to go up and down
4. before and after (as in 上下文[shang4 xia4 wen2] "context")
5. (used after a quantity) approximately; ... or so
6. (in a social hierarchy) the high and the low; seniors and juniors (as in 上下和睦[shang4 xia4 he2 mu4] "harmony between superiors and subordinates")
7. all members of a group (as in 舉國上下|举国上下[ju3 guo2 shang4 xia4] "the entire nation")
8. relative superiority (as in 不相上下[bu4 xiang1 shang4 xia4] "evenly matched")

Study it in Yanamino