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 : development2: 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 region5 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 unit6: an arrangement of a body or group of persons or things in some prescribed manner or for a particular purpose <flying in formation>