Definition of the kiss

Prof. of Computer Science:
A kiss is a few bits of love compiled into a byte.
Prof. of Algebra:
A kiss is two divided by nothing.
Prof. of Geometry:
A kiss is the shortest distance between two straight lines.
Prof. of Physics:
A kiss is the contraction of mouth due to the expansion of the heart.
Prof. of Zoology:
A kiss is the interchange of unisexual salivary bacteria.
Prof. of Physiology:
A kiss is the juxtaposition of two orbicular ors muscles in the state of contraction.
Prof. of Dentistry:
A kiss is infectious and antiseptic.
Prof. of Accountancy:
A kiss is a credit because it is profitable when returned.
Prof. of Economics:
A kiss is that thing for which the demand is higher than the supply.
Prof. of Philosophy:
A kiss is the persecution for the child, ecstasy for the youth and homage for the old.
Prof. of Engineering:
Uh, What? I’m not familiar with that term.