| PP | diphosphate group; emphysema [pink puffers]; near point of accommodation [Lat. punctum proximum]; pa... |
|---|---|
| PS | pacemaker syndrome; paired stimulation; paradoxical sleep; paraspinal; parasympathetic; Parkinson sy... |
| s | Greek lower case letter sigma; conductivity; cross section; millisecond; molecular type or bond; pop... |
| T90 | time required for 90% mortality in a population of microorganisms exposed to a toxic agent |
| TD | the time required to double the number of cells in a given population; thermal death time |