delta function

14 LETTERS · STARTS WITH D

delta function is a valid 14-letter word worth 19 points in Scrabble and 24 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

D2E1L1T1A1F4U1N1C3T1I1O1N1

2 + 1 + 1 + 1 + 1 + 0 + 4 + 1 + 1 + 3 + 1 + 1 + 1 + 1 =19 PTS

DOUBLE WORD → 38TRIPLE WORD → 57

MEANING

What does delta function mean?