Etymology of the Latin word philtrum
the Latin word philtrum (love-potion)
derived from the Greek word philtron, φίλτρον (love potion, anything that awakens love)
derived from the Greek word philein
derived from the Greek word philos, φίλος (loving; actively, fond; friendly (still as a noun, an associate, neighbor, etc.))
derived from the Greek word phileo, φιλέω (to be a friend to (fond of (an individual or an object)); have affection for ; specially, to kiss (as a mark of tenderness))