"In apposition to a place name, as London town" (OED).

Mrs. Bennet is so upset with Elizabeth not accepting the proposal because in the late 18th century getting married was important for young ladies, for future economic concerns, especially for those women who wouldn't be left anything after their father's death (Maurer, Courtship and Marriage).

"Marriage between members of different families, castes, tribes, nations, or societies, as establishing a connection between such families, etc." (OED).

Grosvenor Street was a respected street in London. In 1735, some of the houses on this street were owned by Dukes, Earls, Ambassadors and Churchmen. Living on a street with other people with titles such as these gave the person living there a certain status of upper quality (Sheppard, Grosvenor Street: Introduction, 33-35).

In the 18th century, dinner was the main meal of the day and it was especially eventful if there were guests invited. The number of courses often changed but essentially each course would offer something different, one might be a soup and the next a meat. Based off of the Bennet's status they probably would have eaten cheaper meat like mutton (Porter, 18th- Century Food).

"paper which has been pressed between heated metal plates or rollers during manufacture to flatten and smooth the surface" (OED).