The capital greek letter (capital delta) is used in math to represent change. Typically, the symbol is used in an expression like this:
In plain language, this means the change in the variable .
Symbol  Format  Data 

Δ  Unicode 

TeX 


SVG 
The slope of a line is calculated by finding the change in y over the change in x using two points on the line.
The Greek letter delta (δ).