* Noun: A weapon for shooting arrows (e.g. "He used his bow to hunt.")
* Noun: A knot or loop (e.g. "She tied a bow in her hair.")
* Verb: To bend the head or upper body in respect or greeting (e.g. "She bowed to the queen.")
* Verb: To bend or curve (e.g. "The tree bowed under the weight of the snow.")
To figure out which part of speech "bow" is, you need to look at the context of the sentence!