A member of a small defensive force of soldiers

In exchange for land, a knight agrees to be a sort of sub-vassal to a vassal. this agreement was known as: investiture homage tyranny subinfeudation

The social contact theory states that

Jackie went to the grocery store to pick up yogurt, bread, and apples. first, she picked up a hand basket for carrying her groceries, and then she searched the store. after finding what she needed, she stood in a check-out line. then, the cashier put her items in a plastic bag, and soon after, jackie left the store. as readers of this event, we understand that jackie paid for the groceries, even though it wasn't mentioned, because we are relying on a grocery store