Old Style

Collins Concise English Dictionary © HarperCollins Publishers::

Old Style noun

1. the former method of reckoning dates using the Julian calendar
   Compare New Style

WordReference Random House Unabridged Dictionary of American English © 2025

old′ style′, 

1. Printing Also, old′style′. a type style differentiated from modern by the more or less uniform thickness of all strokes and by slanted serifs.
2. Time (caps.) time reckoned according to the Julian calendar. Cf. New Style. 
3. Printing Also, old′-style′. [Typography.] noting or descriptive of a font of numerals of which some part extends below the baseline.
• 1865–70

Collins Concise English Dictionary © HarperCollins Publishers::

old style noun

1. a type style reviving the characteristics of old face