isogloss

UK: /ˈaɪsəʊˌɡlɒs/ US: (ī′sə glos′, -glôs′)

WordReference Random House Unabridged Dictionary of American English © 2025

i•so•gloss  (ī′sə glos′, -glôs′), n. 

1. Linguistics (in the study of the geographical distribution of dialects) a line on a map marking the limits of an area within which a feature of speech occurs, as the use of a particular word or pronunciation.

• German (1892); see iso-, gloss²

i′so•glos′sal, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

isogloss / ˈaɪsəʊˌɡlɒs/ noun

1. a line drawn on a map around the area in which a linguistic feature is to be found, such as a particular pronunciation of a given word

ˌisoˈglossal, ˌisoˈglottic, ˌisoˈglossic, ˌisoˈglottal adjective