The Mayflower was the ship used to transport roughly 100 people (primarily families) across the Atlantic Ocean to head to Jamestown. Most people who went on the ship did so to escape the religious persecution of King Charles. However, the ship got caught in a storm and instead of heading to Jamestown, they found themselves on present-day Cape Cod
Religious Persecution was getting attacked based on your religious beliefs. Most people did so to escape the religious persecution of the protestants, along with King Charles.
Thanksgiving was the celebration of a good harvest. The Pilgrims and the Wampanoag (Wom-puh-know-agh) Indians got together and celebrated the first Thanksgiving in November of 1621.
A charter is a piece of paper stating their goals and what they are going to do once they get to their destination. In the case of the Puritans, they had a charter to go to Virginia and settle their (about) 100 people. Unfortunately, they didn't make it to Virginia, and instead the Puritans settled in Massachusetts