[ ahy-suh-graf, -grahf ]
/ ˈaɪ səˌgræf, -ˌgrɑf /


(in the study of the geographical distribution of a dialect) a line drawn on a map to indicate areas having common linguistic characteristics.

Origin of isograph

First recorded in 1935–40; iso- + -graph
Related formsi·so·graph·ic [ahy-suh-graf-ik] /ˌaɪ səˈgræf ɪk/, i·so·graph·i·cal, adjectivei·so·graph·i·cal·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019