Here's a breakdown:

* Waves are disturbances that transfer energy without transferring matter.

* Mediums are the materials that allow the waves to propagate. Think of it as the path or "highway" the wave travels along.

Examples:

* Sound waves: Travel through mediums like air, water, or solids.

* Water waves: Travel through the surface of water.

* Light waves: Can travel through a vacuum (like space) as well as mediums like air and glass.

Key point: While some waves can travel through a vacuum, most waves require a medium to propagate.