Adapted by the rationalists from an older esoteric term, an egregore is a collective entity (of persons) that seems to act like a being in its own right, like "America" or "Microsoft", although they need not be legally recognized to qualify.
It's unclear to what extent these entities can be called "minds" (or "conscious"), but your own mind is also made up of a collective (of neurons). "In truth, there are only atoms and the void," and yet we give names to higher-order structures, like individuals.
See also, memetics, reductionism...