Note 1: (tambour frame)
A tambour frame will be familiar to most people who know anything about embroidery. It consists of two nested hoops which hold a piece of fabric taut during the stiching process. Here's a link from the Encyclopeadia Britannica: tambour.
Note 2: (demesnes)
From the American Heritage Dictionary:
1. Law Possession and use of one's own land. 2. Manorial land retained for the privateuse of a feudal lord. 3. The grounds belonging to a mansion or country house. 4. An extensive piece of landed property; an estate. 5. A district; a territory. 6. A realm; a domain.
Note 3: (Mansfield-common)
Austen had used the form "Mansfield common" prior to this occurrence, but here chooses to hyphenate the two words. Similarly, through much of Persuasion, place names are given as: "Kellynch-hall" or "Union-street". Here in Mansfield Park, it is more often written in the more familiar: "Mansfield Park" form.