There is a total of 85689 clues beginning with o
- One of the Princetonians
- One of the principal cards in skat
- One of the principal centers of French Protestantism
- One of the principal deities in Hinduism
- One of the principal English cheeses
- One of the principles of Kwanzaa
- One of the Prize guys
- One of the Prozorov sisters
- One of the Puritans
- One of the Quad Cities
- One of the Quad Cities, in Illinois
- One of the Quechuan people
- One of the Queen's pets
- One of the Queens
- One of the quick assets
- One of the Quints
- One of the R's in JRR Tolkien
- One of the R's in R&R
- One of the R's in the USSR
- One of the R's of R&R
- One of the R's, synonymously
- One of the race of man
- One of the races
- One of the racing also-rans in 1963's "Hey Little Cobra"
- One of the racing Andrettis
- One of the rails
- One of the Ramones
- One of the rank and file
- One of the rappers
- One of the rare earths
- One of the Rasenna
- One of the Rat Islands
- One of the Rat Pack
- One of the rationed foods
- One of the ratites
- One of the ratites
- One of the Rayong throng
- One of the Reagans
- One of the recent frosh
- One of the record industry's former Big Four
- One of the red Avenues
- One of the red Monopoly spaces
- One of the red wines
- One of the Redgrave sisters
- One of the Redgraves
- One of the Reds' rivals
- One of the reds
- One of the reeds
- One of the reeds
- One of the ref's set
- One of the regions
- One of the reindeer
- One of the Reiners
- One of the renters in Steinbeck's "Tortilla Flat"
- One of the reputed Dead Sea Scrolls authors
- One of the reputed Dead Sea Scrolls writers
- One of the Rhine Maidens
- One of the Rice Krispies elves
- One of the Rice Krispies mascots
- One of the Rice Krispies sounds
- One of the ridges on brain surface
- One of the Righteous Brothers
- One of the Ringling Brothers
- One of the rings on a target
- One of the Ritters
- One of the rivers near Three Rivers Stadium
- One of the rivers of Three Rivers Stadium
- One of the Rivieras
- One of the roads that led to Rome
- One of the Robinsons
- One of the Rockefellers
- One of the Rockefellers
- One of the Rockets' "Twin Towers"
- One of the rockets
- One of the Rockies: Abbr
- One of the Rocky films
- One of the Rocky Mountain States
- One of the Rocky Mountain States: Abbr
- One of the Rolling Stones
- One of the Roman Fates
- One of the Roman Fates
- One of the Roman Parcae
- One of the Romneys
- One of the rooms in Clue
- One of the Roosevelts
- One of the Roosevelts
- One of the Rosenbergs
- One of the Rosetta Stone languages
- One of the Rosses
- One of the Rossettis
- One of the royal family
- One of the Royals?
- One of the Roys
- One of the Roys on "Succession"
- One of the Rubbles
- One of the Rubinsteins
- One of the Rug Rats
- One of the Ryder Cup teams
- One of the S's in USS
- One of the SSRs