A massive collapsed star is a dead star.
A collapsed star is a term used to describe a "dead" star, which is a star that has come to the end of its lifetime and just collapses on itself. A black hole
black dwarf or neutron star
bonorn the north star is a name its also called. some say its at the head of the solar system.
White Dwarf
A black hole
It seems you are referring not to any collapsed star, but a black hole. The "event horizon" is the area from which nothing can escape.
It contains the entire collapsed star, however the star has collapsed to an infinitesimal point (or infinitesimally thin ring if its spinning) singularity, leaving everything around that totally empty except for warped spacetime (which is what causes gravity).
Yes. A black hole is a collapsed star.
A black hole.
Neutron Star
Depending on how big the star was, it could be a white dwarf, a neutron star, or a black hole.