Noah Webster's New International Dictionary of the English Language

1. (v. t.) To make sharp, keen, or eager; to excite; to stimulate; as, to whet the appetite or the courage.

2. (v. t.) To rub or on with some substance, as a piece of stone, for the purpose of sharpening; to sharpen by attrition; as, to whet a knife.

3. (n.) The act of whetting.

4. (n.) That which whets or sharpens; esp., an appetizer.