diglossia

[dahy-glos-ee-uh, -glaw-see-uh]

noun

the widespread existence within a society of sharply divergent formal and informal varieties of a language each used in different social contexts or for performing different functions, as the existence of Katharevusa and Demotic in modern Greece.
Pathology. the presence of two tongues or of a single tongue divided into two parts by a cleft.

Origin of diglossia

1955–60; Latinization of French diglossie, equivalent to Greek díglōss(os) speaking two languages (see diglot) + French -ie -y3
Related formsdi·glos·sic [dahy-glos-ik] /daɪˈglɒs ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for diglossia

diglossia

noun

linguistics the existence in a language of a high, or socially prestigious, and a low, or everyday, form, as German and Swiss German in Switzerland

Word Origin for diglossia

C20: New Latin, via French, from Greek diglōssos speaking two languages: see diglot
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

diglossia in Medicine

diglossia

[dī-glŏsē-ə]

n.

bifid tongue
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.