Mis-nō'mer, n.
n. [From O. Fr. mes, amiss, wrong, from Lat. minus, less, and Fr. nommer, to name, Lat. nominare, from nomen, name.]
Sense 1. (Law.) The mistaking of the true name of a person; the using of one name for another; a misnaming. “Many of the changes, by a great misnomer, called parliamentary ‘reforms.’” Burke.
Sense 2. A wrong or inapplicable name or title.
Is Pompey’s Pillar really a misnomer?
Had Thebes a hundred gates, as sung by Homer? H. Smith.
The word “synonym” is in fact a misnomer. Abp. Whately.