Source : Webster's Revised Unabridged Dictionary (1913)

Is \Is\, v. i. [AS. is; akin to G. & Goth. ist, L. est, Gr. ?,
   Skr. asti. [root]9. Cf. {Am}, {Entity}, {Essence}, {Absent}.]
   The third person singular of the substantive verb be, in the
   indicative mood, present tense; as, he is; he is a man. See
   {Be}.

   Note: In some varieties of the Northern dialect of Old
         English, is was used for all persons of the singular.

               For thy is I come, and eke Alain.  --Chaucer.

               Aye is thou merry.                 --Chaucer.

   Note: The idiom of using the present for future events sure
         to happen is a relic of Old English in which the
         present and future had the same form; as, this year
         Christmas is on Friday.

               To-morrow is the new moon.         --1 Sam. xx.
                                                  5.

Source : WordNet®

is
     See {be}

be
     v 1: have the quality of being; (copula, used with an adjective
          or a predicate noun); "John is rich"; "This is not a
          good answer"
     2: be identical to; be someone or something; "The president of
        the company is John Smith"; "This is my house"
     3: occupy a certain position or area; be somewhere; "Where is
        my umbrella?" "The toolshed is in the back"; "What is
        behind this behavior?"
     4: have an existence, be extant; "Is there a God?" [syn: {exist}]
     5: happen, occur, take place; "I lost my wallet; this was
        during the visit to my parents' house"; "There were two
        hundred people at his funeral"; "There was a lot of noise
        in the kitchen"
     6: be identical or equivalent to; "One dollar equals 1,000
        rubles these days!" [syn: {equal}] [ant: {differ}]
     7: form or compose; "This money is my only income"; "The stone
        wall was the backdrop for the performance"; "These
        constitute my entire belonging"; "The children made up the
        chorus"; "This sum represents my entire income for a
        year"; "These few men comprise his entire army" [syn: {constitute},
         {represent}, {make up}, {comprise}]
     8: work in a specific place, with a specific subject, or in a
        specific function; "He is a herpetologist"; "She is our
        resident philosopher" [syn: {follow}]
     9: represent, as of a character on stage; "Derek Jacobi was
        Hamlet" [syn: {embody}, {personify}]
     10: spend or use time; "I may be an hour"
     11: have life, be alive; "Our great leader is no more"; "My
         grandfather lived until the end of war" [syn: {live}]
     12: to remain unmolested, undisturbed, or uninterrupted -- used
         only in infinitive form; "let her be"
     13: be priced at; "These shoes cost $100" [syn: {cost}]
     [also: {were}, {was}, {is}, {been}, {are}, {am}]

Source : Free On-Line Dictionary of Computing

IS
     
        1.  {International Standard}.
     
        2. {Intermediate System}.

is
     
         The {country code} for Iceland.
     
        (1999-01-27)