Meaning of DELTA in English

I. ˈdel-tə noun

Etymology: Middle English deltha, from Greek delta, of Semitic origin; akin to Hebrew dāleth daleth

Date: 13th century

1. : the 4th letter of the Greek alphabet — see alphabet table

2. : something shaped like a capital Greek delta ; especially : the alluvial deposit at the mouth of a river

3. : an increment of a variable — symbol Δ

4. : delta wave

• del·ta·ic del-ˈtā-ik adjective

II. adjective

Date: circa 1929

: fourth in position in the structure of an organic molecule from a particular group or atom — symbol δ

Merriam-Webster's Collegiate English vocabulary.      Энциклопедический словарь английского языка Merriam Webster.