13-Letter Words Starting with O

All 76 thirteen-letter words that start with O

OB

• objectionable26adj. Arousing disapproval; worthy of objection; offensive.
• objectionably29adv. In an objectionable manner.
• objectiveness27n. The characteristic of being objective; neutrality.
• obliviousness18n. The characteristic of being oblivious.
• obnoxiousness22n. The characteristic of being obnoxious.
• observability23n. The state of being observable.
• observational18adj. Relating to observation, especially scientific observation.
• obsessiveness18n. The characteristic of being obsessive.

OC

• occidentalism20n. The habits and attitudes of westerners.
• oceanographer21n. A person who studies oceanography, the science of oceans.
• oceanographic23adj. Relating to oceanography, the science of oceans.

OD

• odontoglossum17n. Any of very many orchids of the genus Odontoglossum.

OF

• offensiveness22n. The quality of being offensive.

OL

• oleomargarine16n. A fatty substance obtained by solidifying purified beef fat, used to...
• oligopolistic18adj. Having the character of, or dominated by, an oligopoly.

ON

• onomatopoetic19adj. Synonym of onomatopoeic.
• ontologically19adv. In an ontological manner.
• onychomycosis28n. Fungal infection of the nail, especially the toenail.

OP

• opacification22n. The action of making something opaque or cloudy.
• operationally18adv. In an operational manner; in accordance with an operation.
• ophthalmology27n. The anatomy, functions, pathology, and treatment of the eye.
• opportunistic19adj. Taking advantage of situations that arise.
• oppositionist17n. A person who opposes; especially a member of an official opposition.

OR

• orbitofrontal18adj. Located in the frontal lobes above the orbits of the eyes.
• orchestration18n. The arrangement of music for performance by an orchestra.
• organogenesis15n. The formation and development of the organs of an organism from...
• organolithium19adj. Describing any organic compound containing a carbon to lithium bond.
• organosilicon16adj. Describing any of a series of derivatives of silicon that have at least...
• orientational13adj. Of or pertaining to orientation.
• ornamentation15n. Decoration, adornment or embellishment.
• ornithischian21n. Any of the order Ornithischia of typically herbivorous dinosaurs that...
• ornithologist17n. A person who studies or practices ornithology.
• oropharyngeal22adj. Of or pertaining to both the mouth and the pharynx.
• orthogonality20n. The property of being orthogonal.
• orthopyroxene28n. Any pyroxene that forms orthorhombic crystals.

OS

• osteochondral19adj. Pertaining to bone and cartilage.
• osteomyelitis18n. An infection of the bone.
• osteonecrosis15n. Avascular necrosis.
• osteopetrosis15n. A rare hereditary disorder characterized by hard, dense bones.
• ostracization24n. The state of being ostracized.

OU

• outmaneuvered19adj. Overcome by the maneuvering of others.
• outspokenness19n. The quality of being outspoken.
• outstandingly18adv. In an outstanding manner.

OV

• overabundance21n. An excess of what is needed or is appropriate.
• overambitious20adj. Excessively ambitious.
• overbearingly22adv. In an overbearing manner.
• overcommitted23adj. Having committed too much of one's time or resources.
• overconfident22adj. Too confident.
• overdeveloped23adj. Overgrown.
• overdiagnosed19adj. Diagnosed more often than it truly occurs.
• overdiagnosis18n. The act or process of diagnosing something too frequently, or based on...
• overdramatize28v. To dramatize to excess; to make overdramatic.
• overemotional18adj. Showing too much emotion.
• overemphasize32v. To place too much emphasis on; to overstate the importance of.
• overexpansion25n. Excessive expansion, especially expansion that is not sustainable.
• overexpressed26adj. Produced by overexpression.
• overextension23n. The state or quality of being overextended; extension beyond normal...
• overhydration23n. Excessive hydration.
• overindulgent18adj. Tending to indulge excessively.
• overleveraged21adj. Subject to excessive leverage (debt).
• overnutrition16n. A form of malnutrition in which nutrients are oversupplied relative to...
• overpopulated21adj. Having or consisting of a higher population than can be sustained.
• overpotential18n. The difference between the electric potential of an electrode or cell...
• overqualified29adj. Having too many qualifications to be deemed appropriate for a (usually...
• oversaturated17adj. Synonym of supersaturated.
• oversensitive19adj. Having excessive sensitivity; reacting to stimuli too readily...
• overshadowing24n. A dominating shadow or malign influence.
• overstatement18n. An exaggeration; a statement in excess of what is reasonable.
• overstimulate18v. To stimulate to an excessive degree; to expose to excessive stimulation.
• overstretched22adj. Subject to demands that are more than can be reasonably handled.
• overtreatment18n. Excessive treatment, often specifically medical treatment.
• overvaluation19n. An instance of overvaluing.
• overwintering20n. The action of overwintering.
• ovoviviparous24adj. Of or pertaining to such kind of animals such as some reptiles whose...

OX

• oxcarbazepine35n. An anticonvulsant and mood-stabilizing drug used primarily in the...

OY

• oystercatcher23n. Any of several black or pied coastal wading birds in the genus...

Questions about these words

How many thirteen-letter words that start with O are there?

Word.ws lists 76 thirteen-letter words that start with O, plus 994 rare ones.

What are common thirteen-letter words that start with O?

observational, objectionable, opportunistic, ophthalmology, oceanographic, ornamentation, orchestration and operationally.

Which of the thirteen-letter words that start with O has the highest letter score?

oxcarbazepine scores 35 points with the standard letter tile values.

Related word lists

• 13-Letter Words
• Words That Start with O
• 12-Letter Words Starting with O
• 14-Letter Words Starting with O
• Q Words Without U