Source : Webster's Revised Unabridged Dictionary (1913)

Welcome \Wel"come\, v. t. [imp. & p. p. {Welcomed}; p. pr. & vb.
   n. {Welcoming}.] [AS. wilcumian.]
   To salute with kindness, as a newcomer; to receive and
   entertain hospitably and cheerfully; as, to welcome a
   visitor; to welcome a new idea. ``I welcome you to land.''
   --Addison.

         Thus we salute thee with our early song, And welcome
         thee, and wish thee long.                --Milton.

Welcome \Wel"come\, a. [OE. welcome, welcume, wilcume, AS.
   wilcuma a welcome guest, from wil-, as a prefix, akin to
   willa will + cuma a comer, fr. cuman to come; hence,
   properly, one who comes so as to please another's will; cf.
   Icel. velkominn welcome, G. willkommen. See {Will}, n., and
   Come.]
   1. Received with gladness; admitted willingly to the house,
      entertainment, or company; as, a welcome visitor.

            When the glad soul is made Heaven's welcome guest.
                                                  --Cowper.

   2. Producing gladness; grateful; as, a welcome present;
      welcome news. ``O, welcome hour!'' --Milton.

   3. Free to have or enjoy gratuitously; as, you are welcome to
      the use of my library.

   Note: Welcome is used elliptically for you are welcome.
         ``Welcome, great monarch, to your own.'' --Dryden.

   {Welcome-to-our-house} (Bot.), a kind of spurge ({Euphorbia
      Cyparissias}). --Dr. Prior.

Welcome \Wel"come\, n.
   1. Salutation to a newcomer. ``Welcome ever smiles.'' --Shak.

   2. Kind reception of a guest or newcomer; as, we entered the
      house and found a ready welcome.

            His warmest welcome at an inn.        --Shenstone.

            Truth finds an entrance and a welcome too. --South.

   {To bid welcome}, to receive with professions of kindness.

            To thee and thy company I bid A hearty welcome.
                                                  --Shak.

Source : WordNet®

welcome
     adj : giving pleasure or satisfaction or received with pleasure or
           freely granted; "a welcome relief"; "a welcome guest";
           "made the children feel welcome"; "you are welcome to
           join us" [ant: {unwelcome}]

welcome
     n 1: the state of being welcome; "don't outstay your welcome"
     2: a greeting or reception; "the proposal got a warm welcome"

welcome
     v 1: accept gladly; "I welcome your proposals"
     2: bid welcome to; greet upon arrival [syn: {receive}] [ant: {say
        farewell}]
     3: receive someone, as into one's house