Office Order: - issued by competent authority. Office order contains instructions related to office works, change of working hours, instruction on closed holidays, message by senior authorities when they take over some organisation, promotions etc. Office orders are issued periodically like every Monday or on every 1st of month etc. The sequence of the information is pre-decided.
Circular: - An advertisement (usually printed on a page or in a leaflet) intended for wide distribution. It need not be issued by competent authority but generally it is issued by officers or managers. Circulars are for specific purpose or event like meeting, or any other event.
Notice: - A sign posted in a public place as an advertisement. When Govt authorities issue some communication, it is also called as notice e.g. notice by labour officer.
Dinesh V Divekar
14th January 2010 From India, Bangalore