Cilium
Cilium explained in an easy to understand way:
Imagine trying to move a heavy couch across a carpeted floor all by yourself. Just as you might use small, repetitive pushes and pulls to gradually nudge the couch forward, cilia are like tiny oars that propel an organism through its environment. The way each push and pull of your hands moves the couch is similar to how cilia's coordinated movements help an organism navigate through liquid, each hair-like projection acting like a miniature paddle pushing against the water to create motion.
Practice Version
Cilium: Short, hair-like projections that help an organism move. Cilium. Cilia are small, hair-like structures on cells that help them move or sense their surroundings.