Delta is a term used to describe a variety of different things. It is most commonly used to refer to the fourth letter of the Greek alphabet, but it can also be used to refer to a triangular landform, a change in a variable, or a difference between two values. In this crossword, BURKE (5 letters) is an Irish surname, Gamma (5 letters) is the third letter of the Greek alphabet, and SILT (4 letters) is a type of sedimentary material.