the outer boundary of an artifact or a material layer constituting or resembling such a boundary | a specialized bony substance covering the root of a tooth |
a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight | a building material that is a powder made of a mixture of calcined limestone and clay; used with water and sand or gravel to make concrete and mortar |
a superficial aspect as opposed to the real nature of something | something that hardens to act as adhesive material |
information that has become public | concrete pavement is sometimes referred to as cement |
the extended two-dimensional outer boundary of a three-dimensional object | any of various materials used by dentists to fill cavities in teeth |
the outermost level of the land or sea | |