Noah Webster's New International Dictionary of the English Language

1. (n.) A loud calling or crying out; outcry; loud or emphatic utterance; vehement vociferation; clamor; that which is cried out, as an expression of feeling; sudden expression of sound or words indicative of emotion, as in surprise, pain, grief, joy, anger, etc.

2. (n.) A word expressing outcry; an interjection; a word expressing passion, as wonder, fear, or grief.

3. (n.) A mark or sign by which outcry or emphatic utterance is marked; thus [!]; -- called also exclamation point.