1 : a fundamental linguistic unit linking a signifier to that which is signified
2 : any nonverbal action or gesture that encodes a message
3 : a written or printed symbol (as for punctuation)
4 : having an indicated pole (as the distinction between positive and negative electric charges)
5 : any incitement to action
6 : a character indicating a relation between quantities
7 : (astrology) one of 12 equal areas into which the zodiac is divided