infinitesimal
adjective
°Incalculably, exceedingly, or immeasurably minute; vanishingly small.
"Do you ever get the feeling that you are but an infinitesimal speck, swallowed by the vastness of the universe and beyond?"
°Of or pertaining to values that approach zero as a limit.
noun
°A non-zero quantity whose magnitude is smaller than any positive number (by definition it is not a real number).