Why is the inside of a black hole called a singularity?

Answer 1

"Singularity" is a term from Math. It means something that you can get as close to
as you want, but you can never get exactly there, because when you're exactly
there, something about it becomes either infinite or zero.

If present hypotheses explaining black holes are correct, then:

-- A black hole has a large mass but occupies only a point.

-- Its radius, diameter, length, width, height, area, and volume are all zero.

-- Since it has mass but no volume, its mass is finite, but its density is infinite.

-- Since the black hole exists only at a single point, any other mass can be any distance
from it, no matter how small, just as long as the distance isn't zero. And since the mutual
force of gravitational attraction between two masses is inversely proportional to the
distance between them, the force between a black hole and any other mass can be
anything imaginable, no matter how large, and it can get as close to infinite force
as you want it to.

Answer 2

"Singularity" is the word that mathematicians give to a mathematical function which, at some point, stops behaving in an expected fashion; when we plot this on a graph, there are sharp jumps or breaks. If that happens, we can no longer rely on the function.

Our mathematical models of black holes have this sort of mathematical singularity and we can't count on our mathematical models to give reasonable results for that area.

Answer 3

The inside of a black hole is called a singularity because it is a point in space where matter is infinitely dense and the laws of physics as we know them break down. At the singularity, the gravitational pull becomes infinite and the curvature of spacetime becomes so extreme that conventional physics cannot describe what happens.