Meaning of uniformitarian

u•ni•form•i•tar•i•an

Pronunciation: (y"nu-fôr"mi-târ'ē-un), [key]
— adj.
  1. supporting, conforming to, or derived from a theory or doctrine about uniformity, esp. on the subject of geology.
  2. of or pertaining to the thesis that processes that operated in the remote geological past are not different from those observed now.
—n.
  1. a person who accepts or supports a uniformitarian theory.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.