Now, "καλώς ήρθες" (etc) is "welcome" - eg: "Welcome to Greece!", only in that sense.Παρακαλώ (pa-ra-ka-ló)
The same word also means "please."
You're right. The isolated phrase "you're welcome" in English is pretty much exclusively used as a response to "thank you." When I saw the topic I automatically assumed this is the usage ripple was asking about. The words "you're welcome to..." may also be used (with about the same meaning) even before a "thank you" is involved, e.g.: You're welcome to read any of my books whenever you want.*Question to Kev: You can't exclaim "You're welcome!" to a visitor, can you?