Definitions

1. interjection

an expression used to indicate agreement, assent, or acknowledgment

"”That’s a great idea,” said John, and I nodded okay.”

2. adverb

used to express agreement or confirmation

“She said it was okay to leave early.”

3. noun

a condition or state of being acceptable or satisfactory

“The concert was okay, but not the best I’ve seen.”

4. adjective

satisfactory or acceptable

“The food was okay, but the service was terrible.”