This name Theophilos is used twice by Luke, the presumed author of the Gospel of Luke (1:1-4) and the Acts of the Apostles (1:1-2). In simplest terms the first part, Theo means “God” from the Greek word Theos (Θεóς). The second part, philos (φίλος) means “friend”.
Hence, “Friend of God” would be a way of translating this combination of two words into a distinct name. This may be the distinct name or title of the person to whom Luke is writing or it may be a code name for a group who under suspicion or persecution as followers of Jesus Christ.
I have chosen this title to indicate my more theological and philosophical musings as a follower of Jesus Christ.