The Collaborative International Dictionary of English v.0.48:

Royal \Roy"al\, a. [OE. roial, riall, real, OF. roial. reial, F.
   royal, fr. L. regalis, fr. rex, regis, king. See Rich, and
   cf. regal, real a coin, Rial.]
   1. Kingly; pertaining to the crown or the sovereign; suitable
      for a king or queen; regal; as, royal power or
      prerogative; royal domains; the royal family; royal state.
      [1913 Webster]

   2. Noble; generous; magnificent; princely.
      [1913 Webster]

            How doth that royal merchant, good Antonio? --Shak.
      [1913 Webster]

   3. Under the patronage of royality; holding a charter granted
      by the sovereign; as, the Royal Academy of Arts; the Royal
      Society.
      [1913 Webster]

   Battle royal. See under Battle.

   Royal bay (Bot.), the classic laurel (Laurus nobilis.)

   Royal eagle. (Zool.) See Golden eagle, under Golden.

   Royal fern (Bot.), the handsome fern Osmunda regalis. See
      Osmund.

   Royal mast (Naut.), the mast next above the topgallant mast
      and usually the highest on a square-rigged vessel. The
      royal yard and royal sail are attached to the royal mast.


   Royal metal, an old name for gold.

   Royal palm (Bot.), a magnificent West Indian palm tree
      (Oreodoxa regia), lately discovered also in Florida.

   Royal pheasant. See Curassow.

   Royal purple, an intense violet color, verging toward blue.


   Royal tern (Zool.), a large, crested American tern (Sterna
      maxima).

   Royal tiger. (Zool.) See Tiger.

   Royal touch, the touching of a diseased person by the hand
      of a king, with the view of restoring to health; --
      formerly extensively practiced, particularly for the
      scrofula, or king's evil.
      [1913 Webster]

   Syn: Kingly; regal; monarchical; imperial; kinglike;
        princely; august; majestic; superb; splendid;
        illustrious; noble; magnanimous.
        [1913 Webster]

WordNet (r) 3.0 (2006):

royal mast
    n 1: topmast immediately above the topgallant mast