There is a total of 85689 clues beginning with o
- One of five born together, informally
- One of five characters on "The Big Bang Theory" to appear in every episode
- One of five competitive figure skating disciplines
- One of five depicted in this puzzle
- One of five different ones in "sequoia"
- One of five expanses
- One of five faculties
- One of five faculties, generally
- One of five faculties, six for some
- One of five for a dolphin
- One of five for a standard 18-wheeler
- One of five for composer John Williams
- One of five for reporters
- One of five golfers to have won all four of the majors
- One of five great ones
- One of five great waterways
- One of five Greats
- One of five heads
- One of five in "abbreviation" (abbr)
- One of five in "abbreviation": Abbr
- One of five in "Hamlet"
- One of five in "Julius Caesar"
- One of five in "La Bohème"
- One of five in "Macbeth"
- One of five in "Othello"
- One of five in "pronunciation": Abbr
- One of five in a children's rhyme
- One of five in a full house
- One of five in a holiday song
- One of five in a kids' rhyme
- One of five in a limerick
- One of five in a maternity ward delivery
- One of five in a pentagon
- One of five in a Shakespeare play
- One of five in a Yahtzee game
- One of five in catholicism?: Abbr
- One of five in many plays
- One of five in Mariah Carey's range
- One of five in NYC
- One of five in this clue
- One of five in this puzzle
- One of five in Yahtzee
- One of five Iroquoian groups
- One of five lakes
- One of five large bodies of water
- One of five little pigs
- One of five Mrs Borgnines
- One of five Nicholases
- One of five Norse kings
- One of five Norwegian kings
- One of five on "The View"
- One of five on a bingo card
- One of five on a map
- One of five on a starfish
- One of five on an eighteen-wheeler
- One of five on most semis
- One of five on the Chinese flag
- One of five Ontarians
- One of five permanent members of the UN Security Council
- One of five popes
- One of five popes, ironically
- One of five rhyming Greek letters
- One of five rulers
- One of five Spanish kings
- One of five states in which same-sex marriage is legal
- One of five sts yet to have a centennial
- One of five who heeded the directions in the first words of 17-, 25-, 40-, 52- and 66-Across
- One of five, for short
- One of five-and-a-half
- One of five
- One of five: Colloq
- One of flashing speed
- One of Florence Nightingale's concerns
- One of Florida's keys
- One of Florida's keys
- One of Florida's two time zones
- One of folk's Guthries
- One of football's Fearsome Foursome
- One of football's Manning brothers
- One of football's Mannings
- One of football’s Kelce brothers
- One of Formosa's oldest cities
- One of forty
- One of forty with a mule
- One of forty, perhaps
- One of four
- One of four (see 17 Across)
- One of four and of thirteen
- One of four active volcanoes in Italy
- One of four annual periods, in Paris
- One of four archangels
- One of four at an MLB game
- One of four between N Y and Cal
- One of four card suits
- One of four classical elements
- One of four common suits
- One of four costars in "Last Vegas"
- One of four direcciones
- One of four directions in 5-Down
- One of four Evangelists