Source : Webster's Revised Unabridged Dictionary (1913)

Alone \A*lone"\, adv.
   Solely; simply; exclusively.

Alone \A*lone"\, a. [All + one. OE. al one all allone, AS. [=a]n
   one, alone. See {All}, {One}, {Lone}.]
   1. Quite by one's self; apart from, or exclusive of, others;
      single; solitary; -- applied to a person or thing.

            Alone on a wide, wide sea.            --Coleridge.

            It is not good that the man should be alone. --Gen.
                                                  ii. 18.

   2. Of or by itself; by themselves; without any thing more or
      any one else; without a sharer; only.

            Man shall not live by bread alone.    --Luke iv. 4.

            The citizens alone should be at the expense.
                                                  --Franklin.

   3. Sole; only; exclusive. [R.]

            God, by whose alone power and conversation we all
            live, and move, and have our being.   --Bentley.

   4. Hence; Unique; rare; matchless. --Shak.

   Note: The adjective alone commonly follows its noun.

   {To} {let or leave} {alone}, to abstain from interfering with
      or molesting; to suffer to remain in its present state.

Source : WordNet®

alone
     adv 1: without any others being included or involved; "was entirely
            to blame"; "a school devoted entirely to the needs of
            problem children"; "he works for Mr. Smith
            exclusively"; "did it solely for money"; "the burden
            of proof rests on the prosecution alone"; "a privilege
            granted only to him" [syn: {entirely}, {exclusively},
            {solely}, {only}]
     2: without anybody else; "the child stayed home alone"; "he
        flew solo" [syn: {solo}, {unaccompanied}]

alone
     adj 1: isolated from others; "could be alone in a crowded room";
            "was alone with her thoughts"; "I want to be alone"
            [syn: {alone(p)}]
     2: lacking companions or companionship; "he was alone when we
        met him"; "she is alone much of the time"; "the lone skier
        on the mountain"; "a lonely fisherman stood on a tuft of
        gravel"; "a lonely soul"; "a solitary traveler" [syn: {alone(p)},
         {lone(a)}, {lonely(a)}, {solitary}]
     3: exclusive of anyone or anything else; "she alone believed
        him"; "cannot live by bread alone"; "I'll have this car
        and this car only" [syn: {alone(p)}, {only}]
     4: radically distinctive and without equal; "he is alone in the
        field of microbiology"; "this theory is altogether alone
        in its penetration of the problem"; "Bach was unique in
        his handling of counterpoint"; "craftsmen whose skill is
        unequaled"; "unparalleled athletic ability"; "a breakdown
        of law unparalleled in our history" [syn: {alone(p)}, {unique},
         {unequaled}, {unequalled}, {unparalleled}]