1. Plural of niner; people or things numbered nine, or those associated with the number nine.
Usage: informal; often used in sports contexts
2. Members or fans of the San Francisco 49ers, an NFL team.
Usage: informal; sports slang
3. Playing cards or dice showing the number nine.
Usage: informal

Examples

• The niners scored a touchdown in the fourth quarter.
• She's a devoted niners fan and never misses a game.
• He rolled two niners on the dice.
• The niners in the deck were missing from the card game.
• Niners from the university gathered for their reunion.