O
office, department, division, program, institute, center 鈥� Lowercase when not part of the official name.
off-site 鈥� Hyphenated. Also: on-site.
on 鈥� Do not use before a date or day of the week. Exception: when its absence would cause confusion.
The workshop was held Monday.
On Sept. 7, the office will close for the holiday.
Margaret called Ted on Tuesday.
online 鈥� not on-line or on line