Here's what I understand it to be ...
Power dressing: a term used in the 80's for women in business who were just beginning to rise to positions of "power" for the first time after the women's lib movement ... in other words, women were moving up to management. It was a way for women to compete with men on the men's turf ... by wearing tailored suits with big shoulder pads and with either straight pencil skirts or pants, which made a woman look more like a man.
Also, in the 80's there was the movie "Wall Street" and many young men started to dress like Gordon Gecko (not sure if I spelled this correctly) .... yellow ties, suspenders and severely slicked back hair. This was a popular style of "power dressing" for men in the 80's.
Since then it usually means a way of dressing like top management in business... for either men or women.
For a man, a suit is always power dressing, but it's got to be sharply tailored. Sometimes I hear a man refer to a "power tie" which is always part of power dressing for a man, but what it looks like changes, depending on the current style. With one exception .... the diagonally striped tie, which I think originated from prep schools, has always been considered a power tie and continues to be so ... probably because it was first worn by the wealthy students. But other patterns and materials come and go as "power ties". And men do not always wear ties in business, nowadays ... unless they are top managment in a conservative company ... like banking. Right now a white shirt, always a power dressing standard, has been joined by colored shirts and stripes and plaids. So the definition of power dressing has broadened.
Woman don't wear suits much anymore, unless they are older or in politics ... most likely because women are not battleing to compete as much (they have partially arrived ... not at top management often, but certainly in lower and middle management). I would say to today's power dressing for a woman can still be a suit, but more often it would be slim dresses and skirts and still pants, sometimes with a light jacket to add on for more emphasis. So the look has softened ... and women look a bit more feminine in business.
Here's much more detail about the history of "power dressing":
https://en.wikipedia.org/wiki/Power_dressing
Dressed to kill: that's something else. I think the term started in the 40's, but I'm not sure ... maybe something to do with the war? It usually does not refer to working or business attire, but more about dressing for special occasions. It means dressing up in fancy clothing, so that you attract a lot of attention. Same as "dressed to the nines".
It has been announced in the beginning of December 2014, so you will have to wait for a long time (they don't reveal it before that under any circumstances). And I think it has more to do with graphic and industrial design than fashion.
I will consider making a thread
