Source : Webster's Revised Unabridged Dictionary (1913)

Dine \Dine\, v. i. [imp. & p. p. {Dined}; p. pr. & vb. n.
   {Dining}.] [F. d[^i]ner, OF. disner, LL. disnare, contr. fr.
   an assumed disjunare; dis- + an assumed junare (OF. juner) to
   fast, for L. jejunare, fr. jejunus fasting. See {Jejune}, and
   cf. {Dinner}, {D?jeuner}.]
   To eat the principal regular meal of the day; to take dinner.

         Now can I break my fast, dine, sup, and sleep. --Shak.

   {To dine with Duke Humphrey}, to go without dinner; -- a
      phrase common in Elizabethan literature, said to be from
      the practice of the poor gentry, who beguiled the dinner
      hour by a promenade near the tomb of Humphrey, Duke of
      Gloucester, in Old Saint Paul's.

Dining \Din"ing\, n. & a.
   from {Dine}, a.

   Note: Used either adjectively or as the first part of a
         compound; as, dining hall or dining-hall, dining room,
         dining table, etc.

Source : WordNet®

dining
     n : the act of eating dinner