Early 17th century; earliest use found in Peter Heylyn (1599–1662), Church of England clergyman and historian. From classical Latin prōmontoriumpromontory.
Definition of promontorium in US English:
promontorium
nounˌprɒm(ə)nˈtɔːrɪəm
1Promontory. rare.
2Anatomy= "promontory".
Origin
Early 17th century; earliest use found in Peter Heylyn (1599–1662), Church of England clergyman and historian. From classical Latin prōmontorium promontory.