- a forming or being formed
- a thing formed
- the way in which something is formed or arranged; structure
- an arrangement or positioning, as of troops, ships, airplanes in flight, football players, etc.
- Ecol. the major unit of vegetation usually extending over a large area, as the prairie, deciduous forest, tundra, etc.
- Geol. a rock unit distinguished from adjacent deposits by some common character, as composition, origin, type of fossil, etc.
Origin of formationMiddle English formacioun from Old French formation from Classical Latin formatio from past participle of formare: see form