Definition of pH in English:

pH

noun

Chemistry
  • A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid and higher values more alkaline. The pH is equal to −log₁₀c, where c is the hydrogen ion concentration in moles per litre.

    • ‘Additionally, another 5 to 16% is excreted daily into the gastric juices, since TCAs have a pK a of 9.5 and are highly ionized at acid pHs, thereby favoring concentration in the acid stomach.’
    • ‘Non-enzymatic reduction of DHA by reduced glutathione in phosphate buffers of different pHs was also measured in a separate cuvette at the same time.’
    • ‘At relatively alkaline pHs (found under stress), even very low ABA concentrations found in the xylem of well-watered plants will limit leaf growth rate.’
    • ‘Prof. Lilley who had no experience in measuring the pHs of surfactant solutions having a high solids content was surprised to see a 0.3 difference in measurements.’
    • ‘At specific concentrations and pHs, these dyes identified the distribution of macromolecules such as proteins, lipids, nucleic acids, or polysaccharides in the developing egg chamber and other tissues.’

Origin

Early 20th century: from p representing German Potenz ‘power’ + H, the symbol for hydrogen.

Pronunciation

pH

/piːˈeɪtʃ/