Noun: isogloss 'I-su,glós
- The geographical boundary or delineation of a certain linguistic feature; the line marking this on a map
"A major isogloss in American English has been identified as the North-Midland isogloss, which demarcates numerous linguistic features, including the Northern Cities vowel shift";
- heterogloss
Derived forms: isoglosses
Type of: isarithm, isogram, isopleth
Encyclopedia: Isogloss