Referred to by Pepys as “a sister” of his Aunt Wight. L&M note that neither the sister or her husband have been identified. Sometimes in the Diary a sister-in-law is refereed to as a sister. In the Companion, L&M say "There is a difficulty in identifying some of [ Uncle Wight's ] relatives mentioned in the Diary", so "Con" is not alone.
Con is a variant form of Connie (Latin): short form of Constance.
Read more at http://www.thinkbabynames.com/meaning/0/Con#I3edQ…
Chart showing the number of references in each month of the diary’s entries.