The American Printer: A Manual of Typography / Containing practical directions for managing all departments of a printing office, as well as complete instructions for apprentices; with several useful tables, numerous schemes for imposing forms in every variety, hints to authors, etc.

by Thomas MacKellar

Obs.—Obsolete; Observatory; Observation.

Obt. or obdt.—Obedient.

Oct.—October.

O. F.—Odd-Fellow or Odd-Fellows.

O. K.—All correct, (slang.)

Old Test. or O. T.—Old Testament.

Olym.—Olympiad.

Opt.—Optics.

Or.—Oregon.

Orig.—Originally.