What does a delta mean in calculus?

Hint: To know what delta means in calculus firstly we will see what delta actually is then we will see its use in calculus. As we know that delta has a different role in many topics of mathematics but mainly it is used to find the difference between two given values. If we put a delta sign in front of a variable that means we are talking about the difference between the two values of the variable. Calculus is part of mathematics which is the study of continuous change. Using these two definitions we will get our desired answer.

Complete step-by-step answer:
Calculus is the branch of mathematics which deals with continuous change. It can be changed in anything like the limit or in the function etc.

Delta is usually used to denote the change in the values or the difference between the two values of a variable. Let us take an example of a slope of a line as follows:
$m=\dfrac{{{y}_{2}}-{{y}_{1}}}{{{x}_{2}}-{{x}_{1}}}$
We can use delta sign as below:
$m=\dfrac{\Delta y}{\Delta x}$
Where,
$\Delta y={{y}_{2}}-{{y}_{1}}$
$\Delta x={{x}_{2}}-{{x}_{1}}$
We know that differential calculus is a part of calculus where we find the slope of a line or a curve using the rate of change in the points of the $x-y$ coordinates which is done by use of delta sign. Delta is none other than a sign which simplifies the equation in calculus.
Hence delta is a symbol used in calculus like in many other topics of mathematics.

Note: Delta is a four letter of Greek alphabet which means change. It is used as a number, function and also equation in mathematics. Calculus on other hand is a topic in mathematics that deals with the continuous change in the variable.