A little light-hearted fun here.
Shirt - derived from middle English, by definition is worn about the upper body and is long enough to be tucked into the pants.
Blouse - derived from a French word, by definition is worn about the upper body, worn by workmen, artists and peasants. Also a 2nd entry in my Websters indicates that "it is usually a loose fitting garment, worn by women from the neck to the waist."
The U.S. Navy refers to an officers (male/female) [upper garment] as a "blouse" not a shirt. This typical nomenclature goes back many centuries in the Navy. While the U.S. Army refers to the same as a "Shirt" for male/female.
I was educated to believe that in most cases, a 5 button item was a blouse for women, 6 or 7 button with a tail was a shirt for woman, always buttoned over the heart side.
Men always would wear the 7 button shirt with long tail, buttoned over the opposite side from the heart.
Any real reason....beats me. Magazines today to save money have stopped the practice of making sure that a photo reflects the proper side. I notice this rather often any more. Especially with photos of woman in any magazine. Often they are reversed to position the model with respect to the page so that she is looking at you and not away from you the reader.
Hugs
Danielle Marie