From Citizendium, the Citizens' Compendium
- Delta (Greek letter): The 4th letter of the Greek alphabet, written as (upper-case) and (lower-case).
- Delta (geology): Add brief definition or description
- Delta (rocket): Add brief definition or description
- Delta Air Lines: Add brief definition or description
- Delta form: A modular form arising from the discriminant of an elliptic curve: a cusp form of weight 12 and level 1 for the full modular group and a Hecke eigenform.
- Delta function: Sharply peaked function, generalization of the Kronecker delta; a distribution that maps a regular function onto a single function value.
- Kronecker delta: A quantity depending on two subscripts which is equal to one when they are equal and zero when they are unequal.
- : A region in the northwestern part of the U.S. state of Mississippi, adjacent to the Mississippi River — not to be confused with the (geological) delta near the mouth of the river, more than 300km to the south in Louisiana.