Gloss-meters are instruments to measure the reflective qualities of manufactured surfaces. They work by shining a light of known intensity at a surface and measuring the specular reflectance.

Two formal definitions of gloss are:

1. The attribute of surfaces that causes them to have shiny or lustrous, metallic appearance.
2. The mode of appearance by which reflected highlights of objects are perceived as superimposed on the surface due to the directionally selective properties of that surface.