Obliquity is a term commonly used in astronomy and planetary science to refer to the angle between a planet's rotational axis and its orbital plane. In simpler terms, it is the tilt of a planet's axis. This tilt can have significant effects on the planet's climate, seasons, and overall habitability. Studying obliquity in different planets can provide insights into their geological history, atmospheric dynamics, and potential for hosting life. Researchers often analyze the obliquity of planets in our solar system as well as exoplanets to better understand planetary dynamics and evolution.