Over the years, over-use and abuse of the key word-Style and Fashion have tended to transform their original meanings to suit the errors of the abusers. Also their inter-changeable usages have compounded their meanings.
The Merriam Webster's Collegiate Dictionary (11th Edition), defines Fashion as the prevailing (dress) Style during a particular time: and Style as a distinctive manner of (dressing). (Emphasis on dress, dressing for the purpose of this article)
From these meanings, we see that Fashion is an offshoot of Style. Fashion is the prevailing Style of a particular period. People of Style are not necessarily subject to Fashion, but Fashionable people must of necessity conform to the prevailing Style.
Another thing to note is that Fashion revolves, while Style evolves. The evolution of Style has brought about bell-bottoms, jump-ups, high waistbands, etc for men. In the late 60s and early 70s, crazy after Style icon James Brown, men wore bell-buttons trousers and tight-fitting shirts with shoes so high they were variously nicknamed, five foot above sea level, upstairs etc.
In the early 80s, young men copied Michael Jackson's high waist band, jump-up black trouser (show me your stockings) and a white pair of stocks to contrast. Figure out what man will wear those things today.
Several times, attempts have been made to strike a come back for these old skools, but the truth is that better taste will never let them prevail. This is what I mean by evolution.
On the other hand, check out the history of women's dress-from the corset to tight-knee, to micro mini, maxi, ball gown and back to all of them again. They are always in a revolution. What goes around comes around.
Generally speaking, men's wear is more about Style than Fashion, while women's wear is more about Fashion than Style. Although there are couple of women who are more into Style than Fashion. But then fashion is meant to update the woman dress-wise. To keep her nature forever attractive, whether in glamorous or simple Style. That is why Fashion shows are basically about women's wear; an attempt to revive the old with the modern modifications and sway the consumer to the currency of a prevailing Style in an endless cycle.
The few men's wears you may see are only there to carry us along, because at the end of it all, the men pick the top. Fashion designers are hard put as to what to do to men's wear on the run way. They have played us into fashion-by-language; casual, leisure, and the lounge wears; they have tried to call some sport and outdoors; separated them into summer, winter and spring.
But between you and I, it is all a farce. Men's wear will and forever be shirts and trousers. Even the jacket is only a modified shirt padded to keep the wearer warm in cold conditions, which also serves to give among others, the effect of comportment and formality.
Now Style in men's wear is the ability to play the combinations of cloths textures, colors, patterns, fits, and suitability with relevant accoutrements to conform to acceptable dress codes.
And for this, one inalienable factor in creating a good Style is taste. Cultivate a good taste and watch your personal Style (in all facets of life) become an epitome.