Prepositions are relational words. In their most basic senses, they establish a relationship in space between something that can move or change, a TRAJECTOR, and something that is presented as a stationary point of reference, a LANDMARK. To put it another way: Prepositions communicate something about the TRAJECTOR’s position relative to the LANDMARK. Below we find the preposition signals the bird’s location and motion relative to the air, the apple’s location relative to the basket, the cow’s trajectory