1.NounOne of various standard sets of conditions for experimental measurements used to aid reproducibility. Abbreviated as STP. Often elliptically called standard conditions.
2.NounThe international, standard conditions used by the IUPAC to aid reproducibility; a temperature of 0 °C (273.15 K) and a pressure of 1 bar (100 kPa). Abbreviated as STP. Often elliptically called standard conditions.