The Collaborative International Dictionary of English v.0.48:

jocular \joc"u*lar\ (j[o^]k"[-u]*l[~e]r), a. [L. jocularis, fr.
   joculus, dim. of jocus joke. See Joke.]
   [1913 Webster]
   1. Given to jesting; jocose; as, a jocular person.
      [1913 Webster]

   2. Sportive; merry. "Jocular exploits." --Cowper.
      [1913 Webster]

            The style is partly serious and partly jocular.
                                                  --Dryden.
      [1913 Webster]

WordNet (r) 3.0 (2006):

jocular
    adv 1: with humor; "they tried to deal with this painful subject
           jocularly" [syn: jocosely, jocular]
    adj 1: characterized by jokes and good humor [syn: jesting,
           jocose, jocular, joking]