Entropy is a measure of disorder or messiness in a [[system]].
Think of it like measuring how messy your room is: the messier it is, the higher the entropy. In science, especially [[physics]] and chemistry, it helps us understand how energy is spread out in a system and how this spreading changes over time.
Systems naturally move from order (low entropy) to [[disorder]] (high entropy), like a building or your mind, both deteriorate without proper maintenance.