D defs.my
Entry 2 senses Webster, 1913

-ous

· IPA /-əs/
01 suff. An adjective suffix meaning full of, abounding in, having, possessing the qualities of, like; as in gracious, abounding in grace; arduous, …
  1. 1.
    An adjective suffix meaning full of, abounding in, having, possessing the qualities of, like; as in gracious, abounding in grace; arduous, full of ardor; bulbous, having bulbs, bulblike; riotous, poisonous, piteous, joyous, etc.
  2. 2.
    A suffix denoting that the element indicated by the name bearing it, has a valence lower than that denoted by the termination -ic; as, nitrous, mercurous, ferrous, sulphurous, etc., as contrasted with nitric, mercuric, ferric, sulphuric, etc.(Chem.)