'Darwinian' definitions:

Definition of 'Darwinian'

adjective

Of or relating to Charles Darwin's theory of organic evolution; "Darwinian theories"

noun

An advocate of Darwinism

From: GCIDE

Darwinian \Dar*win"i*an\, a. [From the name of Charles Darwin, an English scientist.] Pertaining to Darwin; as, the Darwinian theory, a theory of the manner and cause of the supposed development of living things from certain original forms or elements. [1913 Webster]
Note: This theory was put forth by Darwin in 1859 in a work entitled "The Origin of species by Means of Natural Selection." The author argues that, in the struggle for existence, those plants and creatures best fitted to the requirements of the situation in which they are placed are the ones that will live; in other words, that Nature selects those which are to survive. This is the theory of natural selection or the survival of the fittest. He also argues that natural selection is capable of modifying and producing organisms fit for their circumstances. See Development theory, under Development. [1913 Webster]

From: GCIDE