Ladies of the Beau Monde changed her clothing at least three different times a day depending on the time of day and her activities. Because the aristocracy and upper crust were so steeped in tradition and manners, they had no trouble following the rules. However, I have no doubt that arrivistes and the rising middle class found this custom bewildering.
The term Undress, or dishabille, was the more casual or simpler style of gown worn at home usually in the morning. These were loose, comfortable gowns made with warmer fabrics and had higher necklines than gowns worn later in the day. Ladies often wore a cap in the morning, too. Ladies wore Undress gowns all morning until noon, depending on scheduled outings or visitors. On a quiet day, a lady might wear Undress until four or five in the afternoon. Sometimes undress gowns were quite decorative. Alison Steadman as Mrs. Bennet in the 1996 film version of Sense and Sensibility wore a morning gown in the film that closely resembled an 1815 Ackermann fashion plate. The actresses playing the Dashwood women often wore an apron or pinafore over their dresses when picking herbs or working in the kitchen. I don't know how accurate this is, or if they only did so because they were not overly wealthy and had to be very careful with their clothing.
Mornings were a time for solitude and tending to the house. For the lady of the house, her morning activities were fairly regimented. After rising, dressing, and eating breakfast, she consulted with her cook and housekeeper, and caught up on her correspondence.
Young ladies such as Jane Austen often practiced the pianoforte first thing in the morning. Ladies also read, sewed, wrote letters, made preserves, and oversaw the gardens.
When I'm staying home, I like pajama pants or stretch pants and a big soft T-shirt. (My favorite writing attire) Of course, if I were to tell my husband I planned to wear undress today, he'd imagine something entirely different ;-)
What do you like to wear when you're at home?