1) One who came from the district of Buchanan, a location near Loch Lomond in Scotland. From the Gaelic elements buth, meaning "house" and chanain, meaning "of the canon." 2) An anglicization of the German buchenhain, meaning "beech wood."
A person with this as their first/last name is most likely a weeb or very weird person. This person is most likely to do weird things if you were talking to him.
Tom: "Hey, did you see Daisy at the party?"
Nick: "Yeah. She's such a Buchanan, though. She was acting like she was way too good forthe party."
Gatsby: "I still love her, though."
Skipping out on a meal in an unannounced fashion prior to the completion of the meal, for the purpose of avoiding paying the check. A cheapskate variation of the Irish Goodbye.