There is a total of 85689 clues beginning with o
- One of four famous concerti by 45 Down
- One of four for "The Star-Spangled Banner"
- One of four for a fox
- One of four for a grand slam, for short
- One of four for a grand slam, in brief
- One of four for a square … or 32-Down, literally?
- One of four for a square: Abbr
- One of four for an ostrich
- One of four for Biles in 2016
- One of four for Hepburn
- One of four for the road
- One of four French kings
- One of four generations in a photo
- One of four Holy Roman emperors
- One of four in "'Twas the night before Christmas, when all through the house"
- One of four in "America"
- One of four in "America, the Beautiful"
- One of four in "As I Was Going to St Ives"
- One of four in "Double, double toil and trouble"
- One of four in "Romeo and Juliet"
- One of four in "The Crucible"
- One of four in "The Star-Spangled Banner"
- One of four in 73-Across
- One of four in 80
- One of four in a carat
- One of four in a chess set
- One of four in a crossword grid
- One of four in a deck
- One of four in a grand slam
- One of four in a grand slam: Abbr
- One of four in a rectangle
- One of four in a Scrabble set
- One of four in a square
- One of four in a year
- One of four in an Alda title
- One of four in Earth’s history
- One of four in five
- One of four in Massachusetts: Abbr
- One of four in Minnesota: Abbr
- One of four in Mississippi
- One of four in Mississippi: Abbr
- One of four in most MLB games
- One of four in mythology: Abbr
- One of four in mythology?: Abbr
- One of four in postwar Berlin
- One of four in the heart
- One of four in the human heart
- One of four in this grid
- One of four in this puzzle
- One of four in Wagner's Ring cycle
- One of four islands in Maui County
- One of four items worn by a bride, traditionally
- One of four men who managed both the Mets and Yankees
- One of four on "Abbey Road"'s cover
- One of four on 41 Across
- One of four on a British car
- One of four on a car
- One of four on a diamond
- One of four on a fork
- One of four on a fork, often
- One of four on a fork, usually
- One of four on a keyboard
- One of four on a par-4
- One of four on a Rolls
- One of four on a square
- One of four on a squash court
- One of four on a violin
- One of four on Earth
- One of four on most keyboards
- One of four on Pluto
- One of four on the annual tennis calendar
- One of four on the human body?
- One of four planted by Jesse Owens
- One of four players remaining
- One of four proclaimed by FDR
- One of four purchased for a Monopoly property
- One of four rhyming Greek letters
- One of four rhyming letters
- One of four singing brothers
- One of four singing brothers of the 1950s
- One of four suits
- One of four suits
- One of four with 30
- One of four with 30 days (abbr)
- One of four women with an EGOT
- One of four won by "Rent"
- One of four won by Simone Biles in Rio
- One of four, on most tables
- One of four-on-the-floor
- One of four
- One of four: Slang
- One of Fran's friends
- One of Fran's puppets
- One of France's largest cities
- One of Frank's "Rat Pack"
- One of Frank's 27-Down
- One of Frank's daughters
- One of Frank's exes
- One of Frank's four wives
- One of Frank's Rat Pack pals