- urn city
- urn design
- urn model
- urn problem
- urn sampling
- Urn with human skull ashes
- urobilin
- urobilinogen
- urocanase
- Urochordata
- urochordata
- urocyte
- urodeum
- urodialysis
- urogastrone
- urogenital aperture
- urogenital apparatus
- urogenital diaphragm
- urogenital fold
- urogenital groove
- urogenital membrane
- urogenital mesentery
- urogenital opening
- urogenital organ
- urogenital papilla