The word "to" is an English preposition that means towards or in the direction of. It is used to indicate a goal, purpose or direction. It can be used as a preposition to express motion or progress towards a destination, as well as to indicate the purpose or aim of an action. For example, "I am going to the store" means I am moving towards the store, and "I did it to help" means I performed the action with the intention of helping.