English
coaster
From coast (“edge of the land where it meets an ocean, sea, gulf, bay, or large lake”) + -er (suffix forming agent nouns).
Formed from coast ‘edge of the land where it meets an ocean, sea,…’ + -er
Latin costa ‘rib; side, wall’
Old French coste ‘rib; side; coast’
Middle English coste ‘rib; side of the body’
English coast
The story
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’).
Today it means
noun A person who originates from or inhabits a coastal area.
Language periods are conventional ranges, not dates for this word.
Etymograph / coaster