1. The act of giving form or shape to anything; a forming; a shaping.
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. (Science: geology) mineral deposits and rock masses designated with reference to their origin; as, the siliceous formation about geysers; alluvial formations; marine formations. A group of beds of the same age or period; as, the eocene formation.
5. The arrangement of a body of troops, as in a square, column, etc.
Origin: L. Formatio: cf. F. Formation.