Why is the approximation symbol used in universal algebra?

Question

Why is the approximation symbol "$\approx$" used in universal algebra instead of "is equal to" symbol?

Example: Bergman´s book "Universal Algebra: Fundamentals and Selected Topics ":

Edit: Found some explanation in the book, still not so clear to me though.

Answer 1

I don't know about Bergman, but Burris & Sankappanavar: A Course in Universal Algebra has this to say on page 3:

The symbol “$=$” is used to express the fact that both sides name the same object, whereas “$\approx$” is used to build equations which may or may not be true of particular elements. (A careful study of $\approx$ is given in Chapter II.)