delta Definition

delta
noun deltas

1. The fourth letter of the Greek alphabet.
2. At the mouth of some rivers: an area of silt, sand, gravel or clay, often roughly triangular, formed from sediment deposited by the river as it slows down on entering the relatively still waters of a sea or lake.
3. In classification systems: fourth; one of the fourth grade, the grade below gamma.
4. communications.
In the NATO alphabet: the word used to denote the letter ‘D'.
Form: Delta

Derivative: deltaic
adj

Etymology: 15c in sense 1; 16c in sense 2: Greek, from Hebrew daleth a tent door.