miesiąca

Miesiąc means month and miesiąca is its genitive, of the month. Most Polish dates go straight from the day to the month name, as dnia piątego maja, so miesiąca appears mainly in phrases that point back to a date already given.

Bieżącego miesiąca, of the current month, refers to the month of the record, so read it against the date at the top of the entry. The abbreviation is mies. Months may also be written as Roman numerals, as 13.VI.1864 for 13 June 1864.