Abarim Publications' online Biblical Greek Dictionary
The noun χειλος (cheilos) means lip (or beak, in case of birds), or rather the edge or rim of anything (a goblet, ditch, rivers and lakes). It stems from the widely attested Proto-Indo-European root "gel-", to call, shout or chant, from whence also the English "yell".
In the Classics our noun appears in a handsome array of sayings: to laugh with the lips only (politely, for show), to wet the lips but not the palate (take very small sips), to have one's heart on one's lips (to blabber on about one's feelings), to have a thought on one's lip (as on the tip of one's tongue).
The Hebrew word for lip, namely שפה (sapa), is part of a huge root that deals with edges and borders and the transition thereof (which cleverly relates it to Hermes, the border-crossing messenger). Our English word "lip" (and the Latin labium) are of unclear pedigree, but their similarity to the noun λιψ (lips), from the Proto-Indo-European root "leyb-", to pour, is generally considered accidental.
Our noun χειλος (cheilos), lip, occurs 7 times in the New Testament; see full concordance.