Sediment is made up of small pieces of rock, but it comes in many different sizes. Sediment is made when big rocks weather and break down, as well as when other natural and unnatural things happen.
All pieces of rock that break off of other rocks, no matter how big they are, are called sediment. The main things that break rocks into smaller pieces and move them around are wind, water, and gravity. Depending on what made the sediment move in the first place, it can go a short distance or a long distance, and this movement can cause the rock to get even more worn down. When sediment isn’t being moved, it piles up with other sediment to make rocks or sand.