[Beatles]

What does the ring in the Benzene molecule mean?

[Mitch]

conjugated double bonds.

[Beatles]

what is a  conjugated double bond?

[Albert]

Benzene is a resonance hybrid: this means that benzene has more than one 'correct' Lewis' structures, none of whom can be considered the right one.

Drawing a ring inthe molecule, you stress the fact that benzene has delocalized electrons, thanks to its conjugated double bonds (see below).

[jdurg]

And to simplify it even further, the bonds between the carbon atoms in a benzene ring aren't really double bonds, but they aren't really single bonds either.  Each carbon atom has a normal bond to the carbon atom next to it, but it also has another bond which is not really 'typical'.  In this bond, the electron flows all the way around the entire ring.  It's not centered on any one C-C "bond".  In order to represent this when drawing the structure, it's drawn as a circle inside the benzene ring.  This denotes that there is one standard bond between each of the C atoms and a delocalized bond spread out over all 6 carbon atoms.

[Donaldson Tan]

the ring refers to the pi electron system that arises due to conjugated double bonds. The 2p orbital of each carbon atom in the benzene ring overlaps one another to form a large molecular orbital in the shape of a ring, above and below the benzene ring. The pi electron system occupies this molecular orbital.

[AWK]

http://en.wikipedia.org/wiki/Benzene