What is what part of speech is as?

The word "as" is a versatile word that can function as several different parts of speech depending on its use in a sentence. Some common uses of "as" include:

1. Preposition: When used as a preposition, "as" typically indicates a comparison or relationship between two things. For example, "He is as tall as his brother."

2. Adverb: "As" can also function as an adverb, modifying adjectives and adverbs. For example, "He ran as fast as he could."

3. Conjunction: In some cases, "as" can be used as a conjunction to introduce a comparison or reason. For example, "He behaves as if he owns the place."

Overall, the word "as" is a versatile word that can function as a preposition, adverb, or conjunction depending on its context in a sentence.