Anything (such as a piece of furniture, or a software feature) that is built in, not added as an extra.
Being an essential and permanent part of something.
Being an included feature that normally comes as an extra.
Constructed as a non-detachable part of a larger structure.
Outward or external appearance.
The outside hull of a tangible object.
The overside or up-side of a flat object such as a table, or of a liquid.
The locus of an equation (especially one with exactly two degrees of freedom) in a more-than-two-dimensional space.
To apply a surface to something.
To make (information or facts) known.
To become known or apparent; to appear or be found.
To provide something with a surface.
To bring to the surface.
To come out of hiding.
To work a mine near the surface.
To rise to the surface.