Main Entry: for·ma·tion

Pronunciation: \fȯr-ˈmā-shən\

Function: noun

Date: 15th century

1 : an act of giving form or shape to something or of taking form : development
2 : something that is formed <new word formations>
3 : the manner in which a thing is formed : structure <the peculiar formation of the heart>
4 : a major kind of plant growth (as forest, grassland, or tundra) characteristic of a broad ecological region
5 a : any igneous, sedimentary, or metamorphic rock represented as a unit b : any sedimentary bed or consecutive series of beds sufficiently homogeneous or distinctive to be a unit
6 : an arrangement of a body or group of persons or things in some prescribed manner or for a particular purpose <flying in formation>