meridional ray

meridional ray

[mə′rid·ē·ən·əl ′rā]
(optics)
A ray that lies within a plane which also contains the axis of an optical system.
Mentioned in ?
References in classic literature ?
His naturally dark complexion had assumed a still further shade of brown from the habit the unfortunate man had acquired of stationing himself from morning till eve at the threshold of his door, on the lookout for guests who seldom came, yet there he stood, day after day, exposed to the meridional rays of a burning sun, with no other protection for his head than a red handkerchief twisted around it, after the manner of the Spanish muleteers.