Defn: Serving or having power to refract, or turn from a direct course; pertaining to refraction; as, refractive surfaces; refractive powers. Refractive index. (Opt.) See Index of refraction, under Index. — Absolute refractive index (Opt.), the index of refraction of a substances when the ray passes into it from a vacuum. — Relative refractive index (of two media) (Opt.), the ratio of the sine of the angle of incidence to the sine of the angle of refraction for a ray passing out of one of the media into the other.

REFRACTIVENESS
Re*fract"ive*ness, n.

Defn: The quality or condition of being refractive.

REFRACTOMETER
Re`frac*tom"e*ter (r`frk*tm"*tr), n. Etym: [Refraction + -meter.]
(Opt.)

Defn: A contrivance for exhibiting and measuring the refraction of light.

REFRACTOR
Re*fract"or (r, n.

Defn: Anything that refracts; specifically: (Opt.)

Defn: A refracting telescope, in which the image to be viewed is formed by the refraction of light in passing through a convex lens.

REFRACTORILY
Re*frac"to*ri*ly (r*frk"t*r*l), adv.

Defn: In a refractory manner; perversely; obstinately.