coaster

Etymology

From coast (“edge of the land where it meets an ocean, sea, gulf, bay, or large lake”) + -er (suffix forming agent nouns). Coast is derived from Middle English coste (“rib; side of the body, flank; side of a building; face of a solid figure; coast, shore; bay, gulf; sea; concavity, hollow; boundary, limit; land; country; district, province, region; locality, place; division of the heavens; compass direction; direction; location with reference to direction, side”) [and other forms], from Old French coste (“rib; side of an object; coast”) (modern French côte (“rib; coast; hill, slope”)), from Latin costa (“rib; side, wall”).