Almost.

Reflectivity - yes, it controls the how much the surface can mirror back the environment.

Specular - controls the strength of surface highlights, which are essentially reflections of light sources.

Gloss - controls the smoothness of the surface, and as a result the sharpness/blurriness of the reflections. It can make the difference between a mirror or brushed steel. You can think of the effect like an insanely fine, micro bump map.