* Yo-yo: A toy that consists of a spool with a string wound around it.
* Yacht: A large sailing or motorboat, especially one used for pleasure cruising.
* Yogurt: A fermented milk product.
* Yucca: A plant with stiff leaves and often large, showy white flowers.
* Yukon: A territory in northwestern Canada.
* Yonder: In that place or direction (often used in a poetic or literary context).
* Yolk: The yellow part of an egg.
* Youth: The time of life between childhood and adulthood.
Let me know if you'd like more examples or have a specific category in mind!