Meaning of old style

old' style"

Pronunciation: [key]
  1. a type style differentiated from modern by the more or less uniform thickness of all strokes and by slanted serifs.
  2. (caps.) time reckoned according to the Julian calendar. Cf.
  3. noting or descriptive of a font of numerals of which some part extends below the baseline.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.