A charter is an agreement between two parties. In history, this term is usually used as a means to describe an agreement between a King and a joint stock company. Here is an example of how it can be used in a sentence.
The King of Spain granted a charter to the Virginia Company, giving them permission to establish a colony in the New World.
A joint stock company is a group of investors who contribute money in order to fund an expedition to the New World. The goal of this joint stock company is for investors to make a profit of the new materials found in the New World. Here is an example of this term use din a sentence:
The joint stock company was hopeful that they would make a profit of the trip to the New World that they recently sponsored.