How are odor and electronic structure related to aromaticity?
I can address the part of your query pertaining to odor and nomenclature (more accurately, I can link the UC Davis ChemWiki page that does so and quote it here):

Benzene derived products are well known to be pleasantly fragrant. For this reason, organic compounds containing benzene rings were classified as being &quot;aromatic&quot; (sweet smelling) amongst scientists in the early 19th century when a relation was established between benzene derived compounds and sweet/spicy fragrances. There is a misconception amongst the scientific community, however, that all aromatics are sweet smelling and that all sweet smelling compounds would have a benzene ring in its structure. This is false, since non-aromatic compounds, such as camphor, extracted from the camphor laurel tree, release a strong, minty aroma, yet it lacks the benzene ring in its structure (See figure 1). On the other hand, benzene itself gives off a rather strong and unpleasant smell that would otherwise invalidate the definition of an aromatic (sweet-smelling) compound. Despite this inconsistency, however, the term aromatic continues to be used today in order to designate molecules with benzene-like rings in their structures. For a modern, chemical definition of aromaticity, refer to sections Aromaticity and Hückel's Rule.

You will find (in the linked section on Aromaticity) that presently:

The three general requirements for a compound to be aromatic are:

The compound must be cyclic

Each element within the ring must have a p-orbital that is perpendicular to the ring, hence the molecule is planar.

The compound must follow Hückel's Rule (the ring has to contain 4n+2 p-orbital electrons).



Putting it all together: The historical naming convention for molecules that smelled good is responsible for the term aromatic. It turns out that many of the molecules that fall into the aromatic category happen to be rather stable/unreactive. These molecules happen to have certain physical characteristics which, taken together, are indicative of a molecule being classified as aromatic or not (based on present-day definitions not relating to odor/smell).