Boarder

A person who pays to live and receive meals in someone else's house.

Boarder comes from 'board' meaning table, not wooden plank. In medieval times, 'board' referred to the wooden table where meals were served, and 'boarding' meant receiving meals at someone's table. The phrase 'room and board' literally meant sleeping space plus table privileges. Boarders were paying guests who ate with the family, distinguishing them from mere renters. The shift from 'table' to 'wooden plank' happened because both were made of boards.