the warmest season of the year; in the northern hemisphere it extends from the summer solstice to the autumnal equinox; "they spent a lazy summer at the shore"
the outer boundary of an artifact or a material layer constituting or resembling such a boundary; "there is a special cleaner for these surfaces"; "the cloth had a pattern of red dots on a white surface"
a superficial aspect as opposed to the real nature of something; "it was not what it appeared to be on the surface"
the extended two-dimensional outer boundary of a three-dimensional object; "they skimmed over the surface of the water"; "a brush small enough to clean every dental surface"; "the sun has no distinct surface"
the outermost level of the land or sea; "earthquakes originate far below the surface"; "three quarters of the Earth's surface is covered by water"
one of the quantities in a mathematical proportion
properly related in size or degree or other measurable characteristics; usually followed by `to'; "the punishment ought to be proportional to the crime"; "earnings relative to production"