O.H.M.S.—On His Majesty's Service.

O.K.—"All correct."

Old Test., O.T.—Old Testament.

O.T.—Oklahoma Territory.

Ont.—Ontario.

Ore.—Oregon.

Oz.—ounce.

P., p., pp.—Page; pages; participle.

Pa.—Pennsylvania.

Par.—Paragraph.