- Yard Waste
- The part of solid waste composed of grass clippings, leaves, twigs, branches, and other garden refuse.
- Yellowstone National Park
- The United State's first national park established in 1872 as a protected area. Yellowstone covers grounds from Wyoming, Montana and Idaho.
- Yield Factor
- A factor that accounts for differences between countries in terms of land productivity. Each year, every country has yield factors for cropland, grazing land, forest and fisheries.
