This is the Smoking Jacket. A Victorian men’s coat that mostly men wore when they were said to be smoking tobacco most commonly in their pass-times.
This smoker’s jacket was common for most rich men who could afford cigars or pipes. In general, it was also a source of protection for men’s clothes from the smell of tobacco.
The smoking jacket derives from the Banyan, the dressing gown, and the sack suit, which we now call a suit as of this day. When these three garments merged together around the 19th century, they eventually became the smoking jacket that men wore over their shirts and ties.
Sherlock Holmes is a most common example of a fictional character that is seen wearing a smoking jacket in films, books and TV media, as he is often portrayed as smoking a fancy pipe with tobacco.
It was common amongst men in the late Victorian period for it was their ideal hobby in their pass-times to drink alcohol and smoke tobacco (e.g. cigars, cigarettes, pipes, you name it), for that was ideal and essential to protecting clothes being worn underneath it from the tobacco of cigarettes and cigars.
It was popular throughout the 20th century as well, but it started to decline around the 1950s until the Playboy Magazine came around in 1953. The smoking jacket began t be shown as a different form of fashion accessory.
To this day, it may seem that way but can be essentially brought back not just in movies, but by people who like old fashions and old architecture in general.
Folkwear was behind the patterns that were used for smoking jackets like the one in the photo way at the top of this page. In the image above this text, it was the image most commonly associated with Folkwear sewing and clothing books. In this case, Folkwear was very associated with the making of that smoking jacket itself.
Smoking jackets like the one shown at the top this page may be found at HistoricalEmporium.com as well as Amazon, Etsy, and so forth.
Links to some examples in such websites can be found below.
https://www.amazon.com/Duke-Digham-Smoking-Jacket-Burgundy/dp/B07DCBY9DJ/thecostumersmani
https://www.etsy.com/search?q=smoking%20jacket
https://www.lacma.org/patternproject#2b567c3bfeebbc81166a0fe75778174e