For*ma"tion (fŏr*mā"shŭn),
n. [L. formatio: cf. F. formation.]
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.