Source : Webster's Revised Unabridged Dictionary (1913)

Grail \Grail\, n. [OF. graal, greal, greet, F. graal, gr?al, LL.
   gradalis, gradale, prob. derived fr. L. crater bowl, mixing
   vessel, Gr. krath`r. See {Crater.}]
   A broad, open dish; a chalice; -- only used of the Holy
   Grail.

   Note: The Holy Grail, according to some legends of the Middle
         Ages, was the cup used by our Savior in dispensing the
         wine at the last supper; and according to others, the
         platter on which the paschal lamb was served at the
         last Passover observed by our Lord. This cup, according
         to the legend, if appoached by any but a perfectly pure
         and holy person, would be borne away and vanish from
         the sight. The quest of the Holy Grail was to be
         undertaken only by a knight who was perfectly chaste in
         thought, word, and act.

Grail \Grail\, n. [F. gr[^e]le hail, from gr['E]s grit, OHG.
   griex, grioz, G. gries, gravel, grit. See {Grit.}]
   Small particles of earth; gravel. [Obs.]

         Lying down upon the sandy grail.         --Spenser.

Grail \Grail\, n. [Cf. OF. graite slender, F. gr[^e]te.]
   One of the small feathers of a hawk.

Grail \Grail\, n. [OF. greel, LL. gradale. See {Gradual}, n.]
   A book of offices in the Roman Catholic Church; a gradual.
   [Obs.] --T. Warton.

         Such as antiphonals, missals, grails, processionals,
         etc.                                     --Strype.

Source : WordNet®

grail
     n : (legend) chalice used by Christ at the last supper [syn: {Holy
         Grail}, {Sangraal}]

Source : Free On-Line Dictionary of Computing

GRAIL
     
        Graphical Input Language.
     
        A {flow chart} language entered on a graphics tablet.  The
        graphical follow-on to {JOSS}.
     
        ["The GRAIL Language and Operations", T.O. Ellis et al,
        RM-6001-ARPA, RAND, Sept 1969].
     
        (1995-01-23)