| Term | Definition |
|---|---|
| unbiased | Showing no prejudice for or against something; impartial. Hits - 856 |
| unconstrained | Not restricted or limited Hits - 811 |
| ungulates | A hoofed typically herbivorous quadruped mammal (such as a pig, cow, deer, horse, elephant, or rhinoceros) of a group formerly considered a major mammalian taxon (Ungulata) ? see artiodactyl, perissodactyl Hits - 904 |
| unilaterally | In a way that affects only one side of an organ, the body, or another structure. Hits - 930 |
| urea | A colourless crystalline compound which is the main nitrogenous breakdown product of protein metabolism in mammals and is excreted in urine. Hits - 847 |
| urogenital systems | In vertebrates, the organs concerned with reproduction and urinary excretion. Although their Hits - 862 |
| uterine luteolysis | Luteolysis is the process by which steroid production ceases and the cells that comprise the corpus luteum (CL) undergo cell death. In many, but not all, animals, luteolysis is initiated by Hits - 865 |