What is the meaning of the word "bow"?

Definitions:

front part of a vessel or aircraft noun
- The coxswain sat in the bow of the boat urging the team toward the finish line.
to bend one's back forward from the waist on down verb
- I bowed when the Queen walked through.
to bend one's knee or body, or lower one's head verb
- They bowed before the monarch.
to bend the head or the upper part of the body in a gesture of respect or greeting verb
- They bowed before the monarch.
to play on a string instrument with a bow verb
- I bowed the violin pleasantly by the fireplace.
to yield to another's wish or opinion verb
- The government bowed to the military pressure.