What part of speech is the word crying?

The word "crying" can be either a verb or a noun, depending on its function in the sentence.

Verb:

* Example: The baby is crying. (This is the present participle form of the verb "cry", acting as the main verb.)

Noun:

* Example: I heard the crying of the baby. (Here, "crying" refers to the act of crying, acting as the object of the verb "heard".)

Therefore, you need to look at the context of the sentence to determine the correct part of speech for "crying."