Deltas

noun

1. The fourth letter of the modern Greek alphabet Δ, δ.
2. A landform at the mouth of a river where it empties into a body of water.

   "Nile Delta"

3. The letter D in the ICAO spelling alphabet, which assigns words to letters of the alphabet.
4. The symbol Δ.
5. A small but noticeable effect. Compare epsilon.

   "This will slow the main code path down, but only by delta."