( though "Big Bang" is sort of Tabloid Journalese for the event/s).
"Big Bang" was a perjorative term used by those attached to "steady state" models of the universe. They had no use for a cosmology where the universe has an origin uncomfortably similar to Genesis ("Let there be light"), especially one pioneered by a Jesuit.
Recommended reading: The Day We Found the Universe, Marica Bartusiak, ISBN 978-0-307-27660-5.