I. ˈis-mē-ən noun
Date: 1601
1. : a native or inhabitant of an isthmus
2. capitalized : a native or inhabitant of the Isthmus of Panama
II. adjective
Date: 1603
: of, relating to, or situated in or near an isthmus: as
a. often capitalized : of or relating to the Isthmus of Corinth in Greece or the games held there in ancient times
b. often capitalized : of or relating to the Isthmus of Panama connecting the North American and South American continents