Noun | 1. | ![]() geological formation, formation - (geology) the geological features of the earth hill - a local and well-defined elevation of the land; "they loved to roam the hills of West Virginia" foreland, headland, promontory, head - a natural elevation (especially a rocky one that juts out into the sea) ridge - a long narrow natural elevation or striation incline, slope, side - an elevated geological formation; "he climbed the steep slope"; "the house was built on the side of a mountain" swell - a rounded elevation (especially one on an ocean floor) natural depression, depression - a sunken or depressed geological formation |