AI overview
Per mille is a unit of measurement that expresses parts per thousand, similar to how a percentage expresses parts per hundred. It matters because it allows precise measurement of very small quantities or concentrations, particularly useful in fields like chemistry, environmental science, and salinity measurements where such fine-scale precision is needed.
AI-generated from the Wikipedia summary — may contain errors.
Article
The phrase per mille (from Latin per mīlle 'in each thousand') indicates parts per thousand. The associated symbol is ‰, similar to a per cent sign % but with an extra zero in the divisor.
Major dictionaries do not agree on the spelling, giving other options of per mil, per mill, permil, permill, and permille.