Definition of formation

• n. - The act of giving form or shape to anything; a forming; a shaping.
• n. - The manner in which a thing is formed; structure; construction; conformation; form; as, the peculiar formation of the heart.
• n. - A substance formed or deposited.
• n. - Mineral deposits and rock masses designated with reference to their origin; as, the siliceous formation about geysers; alluvial formations; marine formations.
• n. - A group of beds of the same age or period; as, the Eocene formation.
• n. - The arrangement of a body of troops, as in a square, column, etc.