obviosity, household name, world, maxim, public intellectual, talk of the town, big name, academy, dogma, commonwealth, more...

obscure, esoteric, arcane, abstruse, recondite

public knowledge, known to all, known to many, known to some, known to few, more...

everyone knows,   shared knowledge,   as we all know,   "everybody says so",   everyone knows it,   stock knowledge,   it is well known,   everyone says it,   well known fact