✨📕 The NEW Collegiate Dictionary, 12th Edition
Over 5,000 words added —
Learn More!
✨📕 The NEW Collegiate Dictionary
—
Learn More!
Menu Toggle
Merriam-Webster Logo
Search
Chatbot
Chatbot
Games
Word of the Day
Grammar
Word Finder
Slang
New
Newsletters
Wordplay
Rhymes
Thesaurus
Join MWU
More
Games
Word of the Day
Grammar
Wordplay
Slang
Rhymes
Word Finder
Newsletters
New
Thesaurus
Join MWU
Shop
Books
Merch
Log In
Username
My Words
Recents
Account
Log Out
Est. 1828
Words That Start With O
Browse the Dictionary
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
0-9
bio
geo
« Previous
Next »
-o-
...
obl
oblanceolate
...
obtemperate
obtend
...
octaacetate
octachord
...
odontoid process
Odontolcae
...
officialdom
officiales
...
-oic
-oid
...
oldland
old lang syne
...
olivette
olive tubercle
...
on a tear
on/at first acquaintance
...
one too many
one-to-one
...
on the bias
on the blink
...
oologist
oologize
...
open sea
open season
...
opistho-
opisthobranch
...
opts out
opulence
...
orchiectomies
orchiectomy
...
Oribatidae
Oribatoidea
...
Orotiñas
orotund
...
Osages
Osagian
...
osteosarcomas
osteosarcomata
...
ourebi
Our Father
...
outfoxes
outfoxing
...
out of tune
out of turn
...
outspoken
outspokenly
...
over-and-under
overanimated
...
overdaringly
overdate
...
overglamorize
overglamorized
...
overoffice
over one's dead body
...
oversimple
oversimplification
...
overwhelm
overwhelmed
...
oxidise
oxidiser
...
ozotype
« Previous
Next »
Word of the Day
jaunty
See Definitions and Examples
»
Get Word of the Day daily email!