Possibly a Hebrew place-name (1 Chr 2:24, kjv, nlt). A number of modern translations follow the Septuagint (early Greek translation of the OT) in treating Ephrathah as the name of one of Caleb’s wives instead of a place.
Caleb-Ephrathah
From Tyndale Bible Dictionary, adapted by Mission Mutual. CC BY-SA 4.0.