The whole natural day , or day and night, consisting of twenty- four hours. Enc. Lond. O. 0. 840 OATH o O. O. An abbreviation, In tbe civil law, for “ope consilio,” (q. v.) In American law , tliese letters are used as an abbreviation for ” Orphans’ Court .” O. K. A conventional symbol, of obscure origin, much used iu commercial practice and occasionally in indorsements on legal documents, signifying “correct,” “approved,” “accepted,” “satisfactory,” or “assented to.” See Getchell & Martin Lumber Co. v. Peter- son, 124 Iowa, 599, 100 N. W. 550; Morgan- ton Mfg. Co. v. Ohio River, etc., Ity. Co., 121 N. C. 514, 28 S. E. 474, 61 Am. St. Rep. 079; Citizens’ Rank v. Farwell, 50 Fed. 570, 0 C. C. A. 24; Indianapolis, D. & W. R. Co. v. Sands, 133 Ind. 433, 32 N. E. 722. O. N. B. An abbreviation for “Old Na- tura Brevium.” See NATURA BREVIUM . O. Ni. It was the course of the English exchequer, as soon as the sheriff entered into and made up his account for issues, amerciaments, etc., to mark upon each head “O. Ni.,” which denoted oneratur, nisi habeat suflicientcm exoncrationem, and presently he became the king’s debtor, and a debet was set upon his head; whereupon the parties paravaile became debtors to the sheriff, and were discharged against the king, etc. 4 Inst. 116; Wharton. O. S. An abbreviation for “Old Style,” or “Old Series.”