The Collaborative International Dictionary of English v.0.48:

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.]
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   1. Received with gladness; admitted willingly to the house,
      entertainment, or company; as, a welcome visitor.
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            When the glad soul is made Heaven's welcome guest.
                                                  --Cowper.
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   2. Producing gladness; grateful; as, a welcome present;
      welcome news. "O, welcome hour!" --Milton.
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   3. Free to have or enjoy gratuitously; as, you are welcome to
      the use of my library.
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   Note: Welcome is used elliptically for you are welcome.
         "Welcome, great monarch, to your own." --Dryden.
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   Welcome-to-our-house (Bot.), a kind of spurge (Euphorbia
      Cyparissias). --Dr. Prior.
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