The term "bow" has several meanings depending on its context.
1) In a social setting, it refers to a polite greeting or acknowledgement made by lowering one's head and body slightly while keeping one's eyes level with those of the person being addressed. It is often accompanied by words such as "hello" or "good morning".
2) In sports, particularly archery, bow refers to a piece of equipment used for shooting arrows. It consists of a curved stick (usually made of wood, fiberglass or carbon) with cables and sights attached to it. The string is pulled back by the user and when released, shoots an arrow towards the target.
3) In boating, bow refers to the front end of a ship or boat. It is often used interchangeably with "prow" which means the same thing.
4) Lastly, in music, particularly orchestral music, bow refers to the wooden stick that musicians use to play their instruments such as violin, viola, cello and double bass. The player moves the bow over the strings of the instrument to produce sound.