phosphorous

The word 'phosphorous' is derived from the same classical roots as its elemental counterpart, phosphorus. It originates from the Greek phōsphoros, a compound of phōs (light) and phoros (bearing), literally meaning "light-bringer," an epithet for the Morning Star (Venus). This name was later applied to the chemical element discovered in the 17th century due to its property of glowing faintly in the dark. The adjective-forming suffix '-ous', of Latin origin, is appended to create 'phosphorous', specifying the adjectival form meaning "of or pertaining to phosphorus," particularly in its chemical compounds.

Structure: phosphor (light-bringer) + ous (adjective suffix) - phosphor: From Latin phosphorus, from Greek phōsphoros, meaning "light-bringing" (from phōs 'light' + -phoros 'bearing'). - ous: A suffix of Latin origin (-osus) used to form adjectives meaning "full of" or "having the qualities of".