Optics. A ray with abnormal properties that arises in the course of certain calculations; specifically one that does not obey Snell's law of refraction.
Origin
Late 19th century (in an earlier sense). From pseudo- + ray.
Definition of pseudo-ray in US English:
pseudo-ray
nounˈs(j)uːdə(ʊ)reɪ
Optics. A ray with abnormal properties that arises in the course of certain calculations; specifically one that does not obey Snell's law of refraction.
Origin
Late 19th century (in an earlier sense). From pseudo- + ray.