ETYM Latin, from, face. Related to Face.
Medicine, facial expression, as symptom; general aspect or appearance.
1. The anterior part of the head; the face.
2. The general aspect or habit of a species, or group of species, esp. with reference to its adaptation to its environment.
3. The face of a bird, or the front of the head, excluding the bill.
In geology, any assemblage of mineral, rock, or fossil features that reflect the environment in which rock was formed.
The set of characters that distinguish one facies from another in a given time stratigraphic unit is used to interpret local changes in simultaneously existing environments. Thus one facies in a body of rock might consist of porous limestone containing fossil reef-building organisms in their living positions. This facies might pass on the side into a reef-flank facies of steeply dipping deposits of rubble from the reef, which in turn might grade into an interreef basin composed of fine, clayey limestone.
Ancient floods and migrations of the seashore up or down can also be traced by changes in facies.