Promontory :: Promontory (n.) A high point of land or rock projecting into the sea beyond the line of coast; a headland; a high cape.
Promontory :: Promontory (n.) A projecting part. Especially: (a) The projecting angle of the ventral side of the sacrum where it joins the last lumbar vertebra. (b) A prominence on the inner wall of the tympanum of the ear.