- the act of forming something
"the constitution of a PTA group last year"
"it was the establishment of his reputation"
"he still remembers the organization of the club"

- the fabrication of something in a particular shape

- creation by mental activity
"the formation of sentences"
"the formation of memories"

- a particular spatial arrangement

- an arrangement of people or things acting as a unit
"a defensive formation"
"a formation of planes"

- (geology) the geological features of the earth

- natural process that causes something to form
"the formation of gas in the intestine"
"the formation of crystals"
"the formation of pseudopods"

1. The act of giving form or shape to anything; a forming; a shaping. Beattie.

2. The manner in which a thing is formed; structure; construction; conformation; form; as, the peculiar formation of the heart.

3. A substance formed or deposited.

4. (Geol.) (a) Mineral deposits and rock masses designated with reference to their origin; as, the siliceous formation about geysers; alluvial formations; marine formations. (b) A group of beds of the same age or period; as, the Eocene formation.

5. (Mil.) The arrangement of a body of troops, as in a square, column, etc. Farrow.