"high point of land or rock projecting into the sea beyond the line of a coast," 1540s, from French promontoire (15c.) and directly from Medieval Latin promontorium, altered (by influence of Latin mons "mount, hill") from Latin promunturium "mountain ridge, headland," which is probably related to prominere "jut out" (see prominent)
promontory (n.)
"high point of land or rock projecting into the sea beyond the line of a coast," 1540s, from French promontoire (15c.) and directly from Medieval Latin promontorium, altered (by influence of Latin mons "mount, hill") from Latin promunturium "mountain ridge, headland," which is probably related to prominere "jut out" (see prominent)