the outer boundary of an artifact or a material layer constituting or resembling such a boundary | an indigenous language that contributes features to the language of an invading people who impose their language on the indigenous population |
a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight | any stratum or layer lying underneath another |
a superficial aspect as opposed to the real nature of something | a surface on which an organism grows or is attached |
information that has become public | the substance that is acted upon by an enzyme or ferment |
the extended two-dimensional outer boundary of a three-dimensional object | |
the outermost level of the land or sea | |