Not in the ordinary meaning of the term, but they act pretty much as if they were a hole in reality.
No they are spheres
Answer:
A blackhole is a place where enough matter has gathered so that the force of gravity allows nothing to leave at a certain distance from the center of the mass (critical distance - the event horizon) - it's black because even light can't escape. As a metaphor, the curved sheet of spacetime shows a blackhole as a place in the fabric where the bend in the fabric is so strong nothing can escape; a well or very sharp drop.
Most of the laws of low energy ('normal') physics no longer work at the center of the blackhole - the singularity. Since physics depends on gravity for defining force and mass, yet at the singuality gravity is infinite, regular physcial laws can't apply - the equations make no sense compared with 'normal reality."