| TD | the time required to double the number of cells in a given population; thermal death time |
|---|---|
| TDP | thermal death point; thoracic duct pressure; thymidine diphosphate; total degradation products |
| TDT | terminal deoxynucleotidyltransferase; thermal death time; tone decay test; tumor doubling time |
| tSIDS | totally unexplained sudden infant death syndrome |
| UCOD | underlying cause of death |