from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The fourth letter of the Greek alphabet. See Table at alphabet.
  • n. An object shaped like a triangle.
  • n. A usually triangular alluvial deposit at the mouth of a river.
  • n. A similar deposit at the mouth of a tidal inlet, caused by tidal currents.
  • n. Mathematics A finite increment in a variable.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The fourth letter of the modern Greek alphabet Δ, δ.
  • n. A landform at the mouth of a river where it empties into a body of water.
  • n. The letter D in the ICAO spelling alphabet, which assigns words to letters of the alphabet.
  • n. The symbol Δ.
  • n. A small but noticeable effect, compare with epsilon.
  • n. The set of differences between two versions of a file.
  • n. The angle subtended at the center of a circular arc.

from the GNU version of the Collaborative International Dictionary of English

  • n. The fourth letter of the Greek alphabet (Δ δ), corresponding to d.
  • n. 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.
  • n. The closed figure produced by connecting three coils or circuits successively, end for end, esp. in a three-phase system; -- often used attributively

from The Century Dictionary and Cyclopedia

  • n. The name of the Greek letter Δ, δ, answering to the Latin and English D. See D.
  • n. A triangular island or alluvial tract included between the diverging branches of the mouth of a great river: as, the delta of the Nile, of the Ganges, of the Mississippi, etc.
  • n. In anatomy, a triangular space or surface.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. an object shaped like an equilateral triangle
  • n. a low triangular area of alluvial deposits where a river divides before entering a larger body of water
  • n. the 4th letter of the Greek alphabet


Middle English, from Latin, from Greek, of Phoenician origin; see dl in Semitic roots.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek δέλτα (delta). (Wiktionary)



Log in or sign up to get involved in the conversation. It's quick and easy.

  • 4th letter of the Greek alphabet. Derived from the Phoenician letter 'Dalet' (meaning 'door' or maybe 'fish'!) River deltas are called that because of the uppercase delta (Δ) which is shaped like a river delta.

    June 23, 2008

  • "Blues" makes me think of the Mississippi delta. See Free Association.

    February 6, 2008