In astronomy, what nine-letter portmanteau word, formed on the model of such stars with such names as 'pulsar' or 'quasar', is an alternative name for a black hole?
The word collapsar, short for collapsed star, is an early word for the end product of stellar gravitational collapse, a stellar-mass black hole. The word, used in this sense, is obsolete; but the term "collapsar" now sometimes refers to a specific model for the collapse of a fast-rotating star, as discussed below.