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.
What is Plague? Plague is a disease caused by Yersinia pestis. This bacterium is found in mammals (prairie dogs, rats, squirrels, rabbits, cats) and their fleas in many areas around the world. Occasionally this organism infects humans. Usually fleas from the infected rodents carry the disease to humans.