a. (Geol.) Of, pertaining to, or designating, the view or doctrine that existing causes, acting in the same manner and with essentially the same intensity as at the present time, are sufficient to account for all geological changes. [ 1913 Webster ]

n. (Geol.) One who accepts uniformitarianism, or the uniformitarian doctrine. [ 1913 Webster ]

n. (Geol.) The uniformitarian doctrine. [ 1913 Webster ]