The external surface of a structure, such as the surface of a dam.
(1) The side of a mailpiece with the delivery address. (2) To arrange mail in a uniform orientation, with the delivery address facing forward and the postage stamp, meter stamp, or permit imprint positioned in the upper right corner. (3) The front of a postage stamp that bears the design.
Exposed surface of dam materials (earth, rockfill, or concrete), upstream and downstream. The external surface which limits the structure, see neatlines. The more or less vertical surface of rock exposed by blasting or excavating. The cutting end of a drill hole.
Face has been defined 8 different ways in documents like Hydrologic Terminology, Dam Safety, Insurance Industry Glossary, and 5 more.