phosphorous adjective. 
['fɒsf(ǝ)rǝs] L18.[from PHOSPHORUS + -OUS.]1.  Phosphorescent. 
L18.2.  Chemistry. Containing phosphorus in its lower valency (3). Cf. 
PHOSPHORIC. 
L18.phosphorous acid the crystalline acid HPO(OH)
2. 
 [TahlilGaran] English Dictionary ▲