Source : Webster's Revised Unabridged Dictionary (1913)

Joyous \Joy"ous\, a. [OE. joyous, joious, joios, F. joyeux.See
   {Joy}.]
   Glad; gay; merry; joyful; also, affording or inspiring joy;
   with of before the word or words expressing the cause of joy.

         Is this your joyous city?                --Is. xxiii.
                                                  7.

         They all as glad as birds of joyous prime. --Spenser.

         And joyous of our conquest early won.    --Dryden.

   Syn: Merry; lively; blithe; gleeful; gay; glad; mirthful;
        sportive; festive; joyful; happy; blissful; charming;
        delightful. -- {Joy"ous*ly}, adv. -- {Joy"ous*ness}, n.

Source : WordNet®

joyousness
     n : the emotion of great happiness [syn: {joy}, {joyfulness}]
         [ant: {sorrow}]