What part of speech is outer?

"Outer" can be either an adjective or an adverb, depending on how it's used in a sentence.

Here's how:

* Adjective: Describes a noun. For example, "the outer layer of the onion" or "the outer planets."

* Adverb: Modifies a verb, adjective, or another adverb. For example, "The bird flew outer," meaning it flew to the outside.

Let me know if you have a specific sentence in mind, and I can tell you which part of speech "outer" is functioning as!