n. - A tract of land shaped like the letter delta (/), especially when the land is alluvial and inclosed between two or more mouths of a river; as, the delta of the Ganges, of the Nile, or of the Mississippi.
n. - The fourth letter of the Greek alphabet (/ /), answering to D.
n. - an object having the shape of the capital /.
n. - The closed figure produced by connecting three coils or circuits successively, end for end, esp. in a three-phase system; -- often used attributively, as delta winding, delta connection (which see), etc.