There is a total of 85689 clues beginning with o
- Only matchmaker in town?
- Only member of both OPEC and the British Commonwealth
- Only men's basketball coach to lead three different schools to the NCAA Final Four
- Only Met ever to have a 30-game hitting streak
- Only metal that's liquid at room temperature
- Only Mexican state that borders Baja
- Only mildly sweet
- Only million-selling Beatles single that was a cover
- Only minimally
- Only Mississippi-born Literature Nobelist
- Only mo all four major sports are played
- Only mo that can begin and end on the same day
- Only mo that can begin and end on the same day of the week
- Only mo that can pass without a single full moon
- Only mo that can start and end on the same day
- Only mo without a holiday
- Only money accepted at the Sky Mall?
- Only monosyllabic state
- Only monosyllabic US state
- Only month that starts on a Sunday in 2021
- Only mortal Gorgon in Greek myth
- Only Mouseketeer personally chosen by Walt Disney
- Only movie for which John Wayne won an Oscar
- Only moving part of a Tesla engine
- Only murderer to be named Super Bowl MVP
- Only musical to win Best Picture since "Oliver!" in 1968
- Only musician to hit #1 on the Billboard Hot 100 as both a vocalist and an instrumentalist
- Only NFL franchise to win championships representing three different cities
- Only NFL team ever to go 0-16 for a season
- Only NFL team that doesn't have a logo on its helmets
- Only NFL team with a perfect season (1972)
- Only NL pitcher to win four Cy Young Awards
- Only name used by three 20th-century popes
- Only nation with a Caspian and Indian Ocean coastline
- Only nation with a win in every summer Olympics
- Only national park in New England
- Only native Englishman ever named Doctor of the Church by a pope
- Only NATO member with no standing army
- Only NBA player to shoot at least 50% on field goals, 40% on three-pointers and 90% on free throws for five consecutive seasons
- Only NFC team never to have played in a Super Bowl
- Only NFC team that hasn't played in a Super Bowl
- Only NFC team to never to play in the Super Bowl
- Only NFL coach to have a perfect season
- Only NFL coach with a perfect season
- Only NFL quarterback with more than 10,000 pass attempts
- Only NFL team to lose all 16 games in a season
- Only NFL team with a perfect season
- Only NFL team without a helmet logo, on scoreboards
- Only NL team never to have played in the World Series, briefly
- Only Nobelist besides Marie to win the prize in two fields
- Only non-actor ever chosen as People's Sexiest Man Alive, familiarly
- Only non-rhyming Pac-Man ghost
- Only non-Southern state won by the GOP in '64
- Only non-US MLB team, on scoreboards
- Only non-US MLB team: Abbr
- Only nonagenarian among U S Presidents (1735–1826)
- Only nonrhyming ghost in Ms Pac-Man
- Only nonsentient zodiac symbol
- Only nonvocal instrument in Britten's "A Ceremony of Carols"
- Only nonvocal instrument in Britten's "Ceremony of Carols"
- Only North American marsupials
- Only now and then
- Only number that can be typed with a keyboard's top row
- Only OK
- Only OT book that never mentions God: Abbr
- Only occupant of Vostok I
- Only OK
- Only okay
- Only once in a while
- Only one assigned to a bomb?
- Only one bears the name of a US president
- Only one fed holiday falls on it annually
- Only one fur coat per week, say?
- Only one needing salvation?
- Only one of the 13 Colonies not touching the Atl Ocean
- Only one of the Seven Dwarfs to wear glasses
- Only one of the Seven Dwarfs without a beard
- Only one person can do it
- Only one US prez has had one
- Only one ___ customer
- Only one-syllable state
- Only one-syllable state capital
- Only one-syllable state name
- Only one-word anagram of a day of the week
- Only openings for air?
- Only opera by 17 Across
- Only other state in Alaska's time zone
- Only outfielder besides Winfield to win Gold Gloves in both leagues in the 1900s
- Only Pacific Division NBA team not based in California
- Only Pacific island monarchy
- Only palindromic top-40 song title from a palindromic-name group
- Only part of Egypt in Asia
- Only part of Egypt located in Asia
- Only partly
- Only partner
- Only partner?
- Only patron on "Cheers" to appear in all 275 episodes
- Only penciled in
- Only Pennsylvania county largely north of the 42nd parallel
- Only Pennsylvania county that borders New York and Ohio