Luke or Lucus = "light-giving"
1) a Gentile Christian, the companion of Paul in preaching the gospel and on his many journeys; he was a physician and author of the book of Luke and Acts in the NT
Part of Speech: noun proper masculine
Contracted from the Latin Lucanus; Lucas, a Christian: - Lucas, Luke.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root Λουκᾶς; click on the second column to search for that grammatical form of the root Λουκᾶς; click on the third column to search for that word and grammatical form; click on the total to search for the root Λουκᾶς.