18-letter words containing a, b, u, s
- urban homesteading — homesteading (def 2).
- weberian apparatus — (in certain fishes) a chain of small bones and ligaments connecting the inner ear with the air bladder.
- westinghouse brake — a railroad air brake operated by compressed air.
- white man's burden — the alleged duty of white colonizers to care for nonwhite indigenous subjects in their colonial possessions.