n (cricket) One run scored by hitting the ball and running between the wickets; a single.
n (Internet slang|leet|sarcastic) Used instead of ! to amplify an exclamation, imitating n00bs who forget to press the shift key while typing exclamation points.
n (colloquial) A particularly special or compatible person or thing.
a Of a period of time, being particular; as, one morning, one year.