The enumeration date is as you surmised the actual date the info was recorded. The official enumeration date was 1 June 1850, all questions were to refer to that date. So she probably died sometime between 1 June and Sept 11. Don.
Definition of plague. 1  an annoyance; those children are a damn plague. 2  any large scale calamity (especially when thought to be sent by God) 3  a swarm of insects that attack plants; a plague of grasshoppers. 4  any epidemic disease with a high death rate.
Plague or the plague is a very infectious disease which usually results in death. The patient has a severe fever and swellings on his or her body. ...a fresh outbreak of plague. ...illnesses such as smallpox, typhus and the plague. 3. countable noun.