1. the sign (!) used in writing after an exclamation.
2. this mark sometimes used in writing two or more times in succession to indicate intensity of emotion, loudness, etc.: Long live the Queen!!
3. this mark sometimes used without accompanying words in writing direct discourse to indicate a speaker's dumbfounded astonishment: “His wife just gave birth to quintuplets.” (!) Also called exclama'tion mark".
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.