Meaning of Oxford comma in English:

Oxford comma

noun

  • A comma used after the penultimate item in a list of three or more items, before ‘and’ or ‘or’ (e.g. an Italian painter, sculptor, and architect).

    Also called serial comma

    ‘In the UK, for instance, Oxford University Press goes against general usage by favouring " ize’ word endings (on etymological grounds) and the’Oxford comma’, aka the Harvard or serial comma.’
    • ‘Did you know using the Oxford comma is simply a matter of personal taste?’
    • ‘Others insist on the Oxford comma as in ‘counties like Mayo, Sligo, and Galway’ instead of Mayo, Sligo and Galway’.’

Origin

Acharacteristic of the house style of Oxford University Press.