- omphacite
- Omphale
- omphalosomphalos synonyms
- omphaloskepsis
- Omri
- OMS
- Omsk
- Omuta
- OMW
- onon synonyms
- Ona
- on accounton account synonyms
- on account ofon account of synonyms
- on a dimeon a dime synonyms
- on a first-name basis
- on again
- on-again, off-againon-again, off-again synonyms
- onager
- onagraceous
- on-air
- on a limbon a limb synonyms
- on all fourson all fours synonyms
- on and offon and off synonyms
- on and onon and on synonyms
- on an even keelon an even keel synonyms
- onanism
- onanist
- onanistic
- on a par with
- on a pedestal, put
- on approvalon approval synonyms
- on a rampage
- on a rollon a roll synonyms
- on a shoestring
- Onassis
- Onassis, Jacqueline Kennedy
- on a stringon a string synonyms
- on a tangent
- Oñate
- on balance
- onbeat
- on behalf ofon behalf of synonyms
- on bended knee
- onboard
- on borrowed time, live
- ONC
- on callon call synonyms
- on-camera
- onceonce synonyms
- once and for allonce and for all synonyms
- Once bitten, twice shy
- once in a blue moononce in a blue moon synonyms
- once in a lifetimeonce in a lifetime synonyms
- once in a whileonce in a while synonyms
- Once more unto the breach, dear friends
- once-overonce-over synonyms
- once-over-lightly
- oncer
- once upon a timeonce upon a time synonyms
- onchocerciasis
- oncidium
- on cloud nineon cloud nine synonyms
- onco-
- oncogene
- oncogenesis
- oncogenic
- oncogenicity
- oncolite
- oncology
- oncomingoncoming synonyms
- on commission
- on condition that
- on consignment
- oncornavirus
- oncost
- OND
- Ondaatje
- on deckon deck synonyms
- on demand
- ondes Martenot
- ondine
- onding
- on dit
- Ondo
- ondograph
- on draft
- on dutyon duty synonyms
- oneone synonyms
- one-a-cat
- one-acter
- one and allone and all synonyms
- one and onlyone and only synonyms
- one and the sameone and the same synonyms
- one anotherone another synonyms
- one-armed banditone-armed bandit synonyms
- on earth
- on easy street
- one-baggerone-bagger synonyms
- one-base hit
- one by oneone by one synonyms
- on edgeon edge synonyms
- one-dimensionalone-dimensional synonyms
- one-down
- one-drop rule
- one-eightyone-eighty synonyms
- one-eyed
- one eye on
- one fell swoop, in
- onefold
- one foot in the grave, have
- one for the booksone for the books synonyms
- one for the roadone for the road synonyms
- Onega
- Onega Bay
- One good turn deserves another
- Oneg Shabbat
- one-handed
- one-horse
- one-horse townone-horse town synonyms
- Oneida
- Oneida Community
- Oneida Lake
- One if by land, and two if by sea
- O'Neill
- O'Neill, Eugene
- one in a millionone in a million synonyms
- oneiric
- oneiro-
- oneirocritic
- oneirocriticism
- oneiromancy
- one jump ahead
- one-legged
- one-linerone-liner synonyms
- one-lung
- one-lunger
- one-man
- one-man show
- One man's meat is another man's poison
- one-many
- on endon end synonyms
- onenessoneness synonyms
- one-nighterone-nighter synonyms
- one-night standone-night stand synonyms
- one-note
- one of a kindone of a kind synonyms
- one-off
- one of these daysone of these days synonyms
- one of those days
- one old cat
- one-one
- one-on-oneone-on-one synonyms
- Oneonta
- one on, that's
- one-parent family
- one picture is worth a thousand words
- one-pieceone-piece synonyms
- oneroner synonyms
- one-reeler
- One rotten (or bad) apple spoils the barrel
- onerousonerous synonyms
- cup of tea, one's
- days are numbered, one's
- ears are burning, one's
- oneselfoneself synonyms
- eyes are bigger than one's stomach, one's
- heart goes out to, one's
- heart misses a beat, one's
- heart sinks, one's
- one-shotone-shot synonyms
- one-sidedone-sided synonyms
- onesie
- one-size-fits-all
- lips are sealed, one's
- name is mud, one's
- number is up, one's
- opposite number, one's
- one-spotone-spot synonyms
- one-star
- one-stepone-step synonyms
- tongue hangs out, one's
- one-stop
- one-suiter
- one-tailed
- one that loved not wisely but too well
- One Thousand Guineas
- one-timeone-time synonyms
- one-to-one
- one-track
- one-track mindone-track mind synonyms
- one-trick pony
- Onetti
- one-twoone-two synonyms
- one up
- one-upmanshipone-upmanship synonyms
- one-wayone-way synonyms
- one-way mirror
- one way or anotherone way or another synonyms
- one-way ticketone-way ticket synonyms
- one-woman
- one-worlder
- on faith, take it
- on fileon file synonyms
- on fireon fire synonyms
- on footon foot synonyms
- ONFr.
- ongaonga
- on-glide
- ongoingongoing synonyms
- ongoingsongoings synonyms
- on good termson good terms synonyms
- on handon hand synonyms
- on highon high synonyms
- on holdon hold synonyms
- ONI
- on iceon ice synonyms
- onie
- onigiri
- on in years
- oniomania
- onion
- onion dome
- onion fly
- onion rings
- Onions
- onionskin
- onion snow
- onion weed
- Onitsha
- on its merits
- onium compound
- Onkelos
- on key
- onkus
- onlap
- onlay
- On Liberty
- onliestonliest synonyms
- on-limits
- onlineonline synonyms
- online catalog
- online dictionary
- onliner
- online thesaurus
- onload
- onlookeronlooker synonyms
- onlooking
- onlyonly synonyms
- only-begotten
- only too
- on-message
- on-mike
- onnagata
- on no account
- o.n.o.
- on occasionon occasion synonyms
- on-off
- onomasiology
- onomastic
- onomasticononomasticon synonyms
- onomasticsonomastics synonyms
- onomatology
- onomatopoeiaonomatopoeia synonyms
- Onondaga
- Onondagan
- on one hand
- on one's
- on one's account
- on one's behalf
- on one's best behavior
- on one's doorstep
- on oneself
- on one's feet
- on one's good behavior
- on one's guardon one's guard synonyms
- on one's hands
- on one's headon one's head synonyms
- on one's heels
- on one's high horseon one's high horse synonyms
- on one's home ground
- on one's honor
- on one's last legs
- on one's mind
- on one's ownon one's own synonyms
- on one's own account
- on one's own timeon one's own time synonyms
- on one's part
- on one's say-so
- on one's shoulders
- on one's soapbox
- on one's tail
- on one's toeson one's toes synonyms
- on one's upperson one's uppers synonyms
- on one's way
- on order
- on pain of
- on paperon paper synonyms
- on-peak
- on pins and needleson pins and needles synonyms
- on principle