An executor, like a conservator, is a person assigned by the court to carry out the will of a deceased person. Said person has been deemed legally worthy of the right to control the deceased's affairs and estate(s). Another word frequently used is an administrator.
An executor bond, or administrator bond, is to make sure that the executor fulfills his or her duties properly and according to the last will and testament of the deceased individual. If there is no last will and testament to follow, the executor is expected to follow the jurisdiction as required by law.
Executors are responsible for taking inventory of and protecting the estate's assets, trying to find heirs to the estate, paying off any outstanding debt attached to the estate, making sure the taxes are paid and calculated correctly for the estate, and so on and so forth.
Some states will also require that executors obtain an Executor Bond in order to protect both the deceased individual and the beneficiaries of this individual from dishonest acts such as embezzlement, fraud, and other acts of this sort.
Some people will include in their last will and testament that an Executor Bond is not required.