Source : Webster's Revised Unabridged Dictionary (1913)

Spell \Spell\, v. t. [imp. & p. p. {Spelled}or {Spelt}; p. pr. &
   vb. n. {Spelling}.] [OE. spellen, spellien, tell, relate, AS.
   spellian, fr. spell a saying, tale; akin to MHG. spellen to
   relate, Goth. spill?n.e {Spell} a tale. In sense 4 and those
   following, OE. spellen, perhaps originally a different word,
   and from or influenced by spell a splinter, from the use of a
   piece of wood to point to the letters in schools: cf. D.
   spellen to spell. Cf. {Spell} splinter.]
   1. To tell; to relate; to teach. [Obs.]

            Might I that legend find, By fairies spelt in mystic
            rhymes.                               --T. Warton.

   2. To put under the influence of a spell; to affect by a
      spell; to bewitch; to fascinate; to charm. ``Spelled with
      words of power.'' --Dryden.

            He was much spelled with Eleanor Talbot. --Sir G.
                                                  Buck.

   3. To constitute; to measure. [Obs.]

            The Saxon heptarchy, when seven kings put together
            did spell but one in effect.          --Fuller.

   4. To tell or name in their proper order letters of, as a
      word; to write or print in order the letters of, esp. the
      proper letters; to form, as words, by correct orthography.

            The word ``satire'' ought to be spelled with i, and
            not with y.                           --Dryden.

   5. To discover by characters or marks; to read with
      difficulty; -- usually with out; as, to spell out the
      sense of an author; to spell out a verse in the Bible.

            To spell out a God in the works of creation.
                                                  --South.

            To sit spelling and observing divine justice upon
            every accident.                       --Milton.

Spell \Spell\, v. t. [imp. & p. p. {Spelled}; p. pr. & vb. n.
   {Spelling}.] [AS. spelian to supply another's place.]
   To supply the place of for a time; to take the turn of, at
   work; to relieve; as, to spell the helmsman.

Spelling \Spell"ing\, n.
   The act of one who spells; formation of words by letters;
   orthography.

Spelling \Spell"ing\, a.
   Of or pertaining to spelling.

   {Spelling bee}, a spelling match. [U.S.]

   {Spelling book}, a book with exercises for teaching children
      to spell; a speller.

   {Spelling match}, a contest of skill in spelling words,
      between two or more persons.

Source : WordNet®

spelling
     n : forming words with letters according to the principles
         underlying accepted usage