Definitions of a KISS:

Prof. of Algebra: a "KISS" is infinity, because it is two divided by nothing (not zero).
Prof. of Geometry: a "KISS" is the shortest distance between two lips.
Prof. of Physics: a "KISS" is the contraction of two mouths, due to the expansion of the heart.
Prof. of Chemistry: a "KISS" is the reaction of an interaction between two hearts.
Prof. of Zoology: a "KISS" is the interchange of friendly salivary bacteria.
Prof. of Physiology: a "KISS" is the juxtaposition of two orbicularis oris muscles in the state of contraction.
Prof. of Dentistry: a "KISS" is both infectious & antiseptic.
Prof. of Accounting: a "KISS" is a credit because it is profitable when returned.
Prof. of Economics: a "KISS" is that thing for which the demand is always higher than the supply.
Prof. of Statistics: a "KISS" is an event whose probability depends on the vital statistics of two minds and hearts.
Prof. of Philosophy: a "KISS" is persecution for the child, ecstasy for youth, and homage for the old.
Prof. of English: a "KISS" is a noun that is used as a conjunction; it is more common than proper; it is spoken in the plural and it is applicable to all.
Prof. of Computer Science: What is a "KISS"? It looks to be an undefined variable, whose possible value can equal love.
Prof. of Architecture: a "KISS" is a process which builds a solid bond between two dynamic objects.