What is Bill Of Store?

Legal Definition
English commercial law. A license granted by custom house officers to merchants, to carry such stores and provisions as are necessary for a voyage, free of duty. See stat. 3 and 4 Will. IV., c. 5 2.
-- Bouviers Law Dictionary
Legal Definition
In English law. A kind of license granted at the custom-house to merchants, to carry such stores and provisions as are necessary for tbeir voyage, custom free. Jacob.
-- Black's Law Dictionary
Legal Definition
A custom-house license exempting a ship’s stores and supplies from duty.
-- Ballentine's Law Dictionary