There are 6,057 words that start with 'o'.
| od | oe | of | oy | oh |
| oi | om | on | op | or |
| os | ow | ox | oaf | oak |
| oar | oat | oba | obe | obi |
| oca | oda | odd | ode | ods |
| oes | off | oxo | oxy | oft |
| ohm | oho | ohs | oil | oka |
| oke | old | ole | oms | one |
| ono | ons | ooh | oot | ope |
| ops | opt | ora | orb | orc |
| ore | ors | ort | ose | oud |
| our | out | ova | owe | owl |
| own | oafs | oaks | oaky | oars |
| oast | oath | oats | obas | obes |
| obey | obia | obis | obit | oboe |
| obol | ocas | odah | odas | odds |
| odea | odes | odic | odor | odyl |
| ofay | oxen | oxes | oxid | oxim |
| oyer | oyes | oyez | offs | ogam |
| ogee | ogle | ogre | ohed | ohia |
| ohms | oils | oily | oink | okas |
| okay | okeh | okes | okra | olds |
| oldy | olea | oleo | oles | olio |
| olla | omen | omer | omit | once |
| ones | only | onos | onto | onus |
| onyx | oohs | oops | oots | ooze |
| oozy | opah | opal | oped | open |
| opes | opts | opus | orad | oral |
| orbs | orby | orca | orcs | ordo |
| ores | orgy | orle | orra | orts |
| oryx | orzo | osar | oses | ossa |
| otic | otto | ouch | ouds | ouph |
| ours | oust | outs | ouzo | oval |
| oven | over | ovum | owed | owes |
| owls | owns | owse | oaken | oakum |
| oared | oases | oasis | oasts | oaten |
| oater | oaths | oaves | obeah | obeli |
| obese | obeys | obias | obits | objet |
| oboes | obole | oboli | obols | occur |
| ocean | ocher | ochre | ochry | ocker |
Note: These 6,057 words that start with 'o' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with ov, ou, or, ob, op, os, oc, ox, ol, on, of, om, od, oo, ot, oi, oa, oe, og, oz, ow, oy, ok, oh, oq.
2-letter words start with 'o' (13)