1.NounA state of being acquainted with a person; originally indicating friendship, intimacy, but now suggesting a slight knowledge less deep than that of friendship; acquaintanceship. .mw-parser-output .defdate{font-size:smaller}
"I know of the man; but have no acquaintance with him."
2.NounA person or persons with whom one is acquainted.
3.NounSuch people collectively; one's circle of acquaintances (with plural concord).
4.NounPersonal knowledge (with a specific subject etc.).