[1] : The Collaborative International Dictionary of English v.0.48

-ous \-ous\suff. of. -ous, us, -os, f. -eux, fr. l. -osus, and
   -us. cf. -ose.
   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.
      1913 webster

   2. chem. 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.
      1913 webster
see also:
-ose -ic 

-Ous >> O Words
-Ous, definition of term: -Ous
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