Definitions

1. adverb

to a degree that is limited to the one mentioned; to a degree that is the least or smallest

“I’ve only eaten half a sandwich.”

2. adjective

limited to the one mentioned; being the least or smallest

“I’ve only got one pen left.”

3. noun

a single item of something

“He’s the only one left on the team.”

4. preposition

used to indicate the extent of something

“I’ve only been here for two days.”