Definition of millesimal in English:


Pronunciation /məˈlesəməl/ /məˈlɛsəməl/


  • Consisting of thousandth parts; thousandth.

    ‘The purity or fineness of silver alloys is now described using the millesimal system in most countries.’
    • ‘The millesimal fineness is usually rounded to a three figure number, particularly where used as a hallmark.’
    • ‘The carat system is increasingly being complemented or superseded by the millesimal fineness system in which the purity of precious metals is denoted by parts per thousand of pure metal in the alloy.’
    • ‘For example, 24-karat gold has a millesimal fineness of 999 and 14-karat gold has a millesimal fineness of 585.’
    • ‘So this scale of potency goes by the name of fifty millesimal potency.’
    • ‘I request my colleagues, especially the beginners in homoeopathy, to try fifty millesimal potency to see if this may be of any help to solve their potency problem.’
    • ‘All Britannia coins have a millesimal fineness of 916 gold.’


  • A thousandth part.

    ‘Maternal and foetal mortality can only be measured in millesimals, and in Hungary there have been about 2,000 planned home births altogether.’
    • ‘The purity is known as its fineness and is measured in millesimals.’
    • ‘In the metric system, employed for most official uses in continental Europe, the grade of gold jewelry is expressed in millesimals.’


Early 18th century from Latin millesimus (from mille ‘thousand’) + -al.