Delta /(dĕl"tȧ)/

pl. Deltas ((-tȧz))

1. A tract of land shaped like the letter delta (Δ), 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.
2. The fourth letter of the Greek alphabet (Δ, δ), corresponding to D.
3. 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. (Elec.)