prevalency

Either from prevalent +‎ -ency or Latin praevalentia.^[1]

prevalency (uncountable)

1. prevalence
   • 1684, John Bunyan, The Pilgrim’s Progress. From This World to That which is to Come: The Second Part. , London: Nathaniel Ponder , →OCLC; reprinted in The Pilgrim’s Progress as Originally Published by John Bunyan: Being a Fac-simile Reproduction of the First Edition, London: Elliot Stock , 1875, →OCLC, page 30:

     Now Chriſtian looked for nothing but death, and began to cry out lamentably, even curſing the time in which he met with Mr. Worldly-Wiſeman, ſtill calling himſelf a thouſand fools for hearkening to his counſel: he alſo was greatly aſhamed to think that this Gentlemans arguments, flowing only from the fleſh, ſhould have that prevalency with him, to forſake the right way.

   • 1689 (indicated as 1690), [John Locke], “The Epistle to the Reader”, in An Essay Concerning Humane Understanding. , London: Eliz Holt, for Thomas Basset, , →OCLC, book I:

     To break in upon this Sanctuary of Vanity and Ignorance, will be, I ſuppoſe, ſome Service to humane Understanding: Though ſo few are apt to think, they deceive, or are deceived in the Uſe of Words; or that the Language of the Sect they are of, has any Faults in it, which ought to be examined or corrected, that I hope I ſhall be pardon’d, if I have in the Third Book dwelt long on this Subject; and endeavoured to make it ſo plain, that neither the inverateneſs of the Miſchief, nor the prevalency of the Faſhion, ſhall be any Excuſe for thoſe, who will not take Care about the meaning of their own Words, and will not ſuffer the Significancy of their Expreſſions to be enquired into.

   • 1848, David Walker, Henry Highland Garnet, Walker's Appeal, with a Brief Sketch of His Life‎:

     I promiscuously fell in a conversation once, with an elderly colored man on the topics of education, and of the great prevalency of ignorance among us: Said he, "I know that our people are very ignorant but my son has a good education: he can write as well as any white man, and I assure you that no one can fool him," etc.

   • 1914, Grant Hague, The Eugenic Marriage, Volume IV. (of IV.)‎:

     Because of its prevalency many mothers treat it with less respect than they should, with the result that fatal complications occur, or the future health of the child is permanently injured. 3.