The Jane Austen Wiki
The Jane Austen Wiki

Augusta Sneyd is the younger sister of Tom Bertram's friend Sneyd. She was on a holiday in Ramsgate with her parents, brother, and sister the September before Mansfield Park takes place. Tom Bertram spent a week with them there, during which he embarrassed Miss Sneyd by paying attention to her younger sister rather than her when Augusta would not be out for another six months.