Source : Webster's Revised Unabridged Dictionary (1913)

Grate \Grate\, n. [LL. grata, fr. L. crates hurdle; or It.
   grata, of the same origin. Sae Crate, Hurdle.]
   1. A structure or frame containing parallel or crosed bars,
      with interstices; a kind of latticework, such as is used
      ia the windows of prisons and cloisters. ``A secret grate
      of iron bars.'' --Shak.

   2. A frame or bed, or kind of basket, of iron bars, for
      holding fuel while burning.

   {Grate surface} (Steam, Boiler) the area of the surface of
      the grate upon which the fuel lies in the furnace.

Grate \Grate\, v. t. [imp. & p. p. {Grated}; p. pr. &. vb. n.
   {Grating}.]
   To furnish with grates; to protect with a grating or
   crossbars; as, to grate a window.

Grate \Grate\, a. [L. gratus agreeable, grateful: cf. It. & Sp.
   grato. See Grace, and cf. Agree.]
   Serving to gratify; agreeable. [Obs.] --Sir T. Herbert.

Grate \Grate\, v. t. [OF grater to scrape, scratch, F. gratter,
   LL. gratare, cratare; of German origin; cf. OHG. chrazz[=o]n
   G. kratzen, D. krassen, Sw. Kratta, and perh. E. scratch.]
   1. To rub roughly or harshly, as one body against another,
      causing a harsh sound; as, to grate the teeth; to produce
      (a harsh sound) by rubbing.

            On their hinges grate Harsh thunder.  --Milton.

   2. To reduce to small particles by rubbing with anything
      rough or indented; as, to grate a nutmeg.

   3. To fret; to irritate; to offend.

            News, my good lord Rome . . . grates me. --Shak.

Grate \Grate\, v. i.
   1. To make a harsh sound by friction.

            I had rather hear a brazen canstick turned, Or a dry
            wheel grate on the exletree.          --Shak.

   2. To produce the effect of rubbing with a hard rough
      material; to cause wearing, tearing, or bruising. Hence;
      To produce exasperation, soreness, or grief; to offend by
      oppression or importunity.

            This grated harder upon the hearts of men. --South.

Source : WordNet®

grate
     v 1: furnish with a grate; "a grated fireplace"
     2: gnaw into; make resentful or angry; "The unjustice rankled
        her"; "his resentment festered" [syn: {eat into}, {fret},
        {rankle}]
     3: reduce to small shreds or pulverize by rubbing against a
        rough or sharp perforated surface; "grate carrots and
        onions"; "grate nutmeg"
     4: make a grating or grinding sound by rubbing together; "grate
        one's teeth in anger" [syn: {grind}]
     5: scratch repeatedly; "The cat scraped at the armchair" [syn:
        {scrape}]

grate
     n 1: a frame of iron bars to hold a fire [syn: {grating}]
     2: a harsh rasping sound made by scraping something
     3: a barrier that has parallel or crossed bars blocking a
        passage but admitting air [syn: {grating}]