BDB508
אֶלְקוֺשִׁי adjective [of a people] with article Nahum the Elkoshite Nah 1:1 (perhaps = from Elkosh, but locality unknown; identified by JerComm. with a village Elcesi in Galilee; compare also Capernaum (= כְּפַר נַחוּם ?); others (improbably) with an Elkosh on east bank of Tigris, near Mosul).
On etymology, and site of place, see DaNahum, etc., 9 ff. GASmTwelve Proph. ii.
79f.