What is what part of speech is last?

"Last" can be used as multiple parts of speech depending on the context in which it is used:

1. As an adjective: In this form, "last" refers to something coming at the end of a series or sequence. For example, "I saw him last night."

2. As an adverb: When used as an adverb, "last" modifies a verb or an adjective to indicate the time when something happened or the position in a sequence. For example, "He arrived last."

3. As a noun: "Last" can also be used as a noun to refer to the object used as a mold in making a shoe.

In summary, "last" can be used as an adjective, adverb, or noun depending on how it is used in a sentence.