There are 2 main definitions of pH in English:

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pH 1

Pronunciation: /piːˈeɪtʃ/


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 −log10 c, where c is the hydrogen ion concentration in moles per litre.
Example sentences
  • 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 relatively alkaline pHs (found under stress), even very low ABA concentrations found in the xylem of well-watered plants will limit leaf growth rate.
  • 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.


Early 20th century: from p representing German Potenz 'power' + H2, the symbol for hydrogen.

Words that rhyme with pH

mph, Rh
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There are 2 main definitions of pH in English:

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PH 2

Entry from US English dictionary

(also P.H.)


1Public Health.
2Purple Heart.
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