first base meaning
EN- NounSUF-ase
- (singular only, baseball) The base after home plate in a counter-clockwise path around a baseball infield.
- The runner took his lead off of first base.
- (singular only, by extension) Completion of the first phase of an activity.
- (singular only, US, colloquial) Kissing, regarded as the first phase of a sexual relationship.
- (blackjack) The betting spot located immediately to the left of the dealer, which is first to receive cards and first to act.
- (singular only, baseball) The base after home plate in a counter-clockwise path around a baseball infield.
Definition of first base in English Dictionary
- Part-of-Speech Hierarchy
- Nouns
- Singularia tantum
- Singularia tantum
- Nouns
Source: Wiktionary
Grammatically, this idiom "first base" is a noun, more specifically, a singularia tantum.