(British, navy) First Officer.

A selective service class denoting that the registrant is already a reserve member of the armed forces or a student taking military training, as in ROTC or an accepted aviation cadet applicant.

(medicine) Once per day, used for prescription directions.

A selective service class denoting that the registrant is only available for noncombat military service due to their conscientious objector status

A selective service class denoting that the registrant a conscientious objector available for alternate service contributing to maintenance of national health, safety, or interest.

A selective service class denoting that the registrant is already a member of the armed forces or also the NOAA or the Public Health Service.

A selective service class denoting that the registrant is not currently subject to induction processing.

A title added before the name of a first sergeant. / A title added before the name of a sergeant first class.

Of telephone numbers dialed in North America, widely used for fictional numbers in television shows, films, and other media.

Synonym of BOGO