Definition of "pseudonym"

I doubt, indeed, whether I should not abandon the struggle altogether—leave this sad world of ordinary life for which I am so ill fitted, abandon the name of Cummins for some professional pseudonym, complete my self-effacement, and—a thing of tricks and tatters, of posing and pretence—go upon the stage.

c. 1911, H. G. Wells, The Obliterated Man

The best example of its literary use so far are the German novel The Golem, by Gustav Meyrink, and the drama The Dybbuk, by the jewish writer using the pseudonym "Ansky".

1928, H.P. Lovecraft, Supernatural Horror in Literature