What is a kiss?

What is a kiss?
In view of
Geometry:
"kiss is the shortest distence between 2 lips!..
Economics:
"kiss is that thing 4 which DEMAND is always higher than SUPPLY!....
PHYSICS:
"kiss is the process of caharging a human body!..
Computer:
"like a LAN, in which 2 bodies r conected without any DATA CABLE!...