O
odd- Follow with a hyphen: odd-looking, odd-numbered.
off- Hyphenate if not listed in Webster's. Examples: off-color, off-season, off-white, offhand, offstage.
-off Hyphenate if not listed in Webster's. Examples: send-off, cutoff, playoff, takeoff.
Office of Public Safety
offices See departments, offices, programs, schools entry.
off of The "of" is unnecessary: She fell off the horse.
OK Not "O.K." or "okay."
one another See each other, one another entry.
online One word in all cases for the computer connection term.
only, just The position of these words can change a sentence's meaning: He only/just seems interested in golf. (He really isn't interested.) He seems interested only/just in golf. (Golf is apparently his only interest.)
Open Space A performance area in the Performing Arts and Radio/Television Center.
out- Hyphenate if not listed in Webster's: outpatient, output, outdated.
-out Hyphenate nouns and adjectives not listed in Webster's: hide-out, walkout, fallout.
out of state See in state, out of state entry.
Oval Capitalize this area of campus: We pitched tents on the Oval. Lowercase in other uses.
over- Follow Webster's. Rarely takes a hyphen: overrated, overexert, overriding.
-over When used as a noun, hyphenate if not listed in Webster's: carry-over, holdover, takeover. When used as a verb, write as two words: Protesters threatened to take over City Hall.