The term setting can refer to the "time, place, and mood" in which a story takes place (Literary Devices, "Setting"). The social setting specifically refers to the way in which society is structured and interacts in a story, which goes hand in hand with time period. Jane Austen's novels were all written between 1795 and 1815 and set between the late 18th and early 19th centuries. The period was known as the Regency Period because King George III was declared to be mad and unfit to rule; hence Prince George served as regent, meaning one who serves instead of the official head of state, until King George III's death, when Prince George was officially crowned as King George IV (BBC, "George IV (1762 - 1830)"). The period starting from King George I until King George IV can also be called the Georgian Period (Gunma Prefectural Women's University, "The Georgian Period: 1714 to 1830"). The period was marked with rapid industrial growth that significantly affected class structures, and its these changes in class structure that Jane Austen alludes to in Pride and Prejudice.
More specifically, due to industrial growth, the 18th century, from the beginning to the end, marked the rise in the middle class in which those of the lower class were now earning enough money to rub shoulders with the landed gentry ("The Georgian Period"). One reason why industry grew was due to the invention of the steam engine, which made goods, especially raw goods much easier to transport. The construction of canals also improved industrial growth because canals allowed for "heavy goods" to be more easily transported. Due to the growth of industry, those who worked as tradesmen in the beginning of the century "developed into professionals" by the end of the century. They became "businessmen, merchants, financiers, shopkeepers and farmers" who were actually earning enough income to "imitate the lifestyle of the richer aristocracy" ("The Georgian Period").
Yet this rise in the middle class created social problems, particularly social prejudices, and its these prejudices that Austen satirizes in her novel. More specifically, those who truly were members of the aristocracy and landed gentry looked down their noses at the tradesmen who were now rich enough to look like the aristocracy and landed gentry. We particularly see Austen satirizing this prejudicial view through the character Lady Catherine de Bourgh who shunned Elizabeth as a match for her nephew due to Elizabeth's trade connections, despite the fact that, though Lady Catherine is titled, Mr. Darcy is only a member of the landed gentry, and as Elizabeth points out, she too is the daughter of land-owning gentleman, as we see when Elizabeth reflects:
He is a gentleman; I am a gentleman's daughter; so far we are equal. (Ch. 56)
Austen further satirizes results of the rise in the middle class through characters like Mr. Bingley and his sisters, whose fortune had been "acquired by trade" (Ch. 4).