Something that is laeotropic turns, twists, or spirals to the left. In biology, it's usually used to describe rare snail shells that twist in a counterclockwise direction.
The word laeotropic is a technical term that is primarily used in the sciences. It comes from the Greek word laios, meaning "left," and the English suffix -tropic, which is derived from the Greek trope, meaning "a turning." While it's most commonly used in biology to describe the spiral pattern of a mollusk's shell, it is also used in physical sciences to describe the way certain substances rotate light. The opposite of laeotropic is dextrotropic, which refers to a rightward or clockwise twist.