Words Starting with O

Browse word origins and etymology

O

The name of the letter O, used in English in exclamations, direct address, and poetic apostrophe.

O'Kane

An Irish surname, an anglicized form of Ó Catháin.

O'odham

An Indigenous Uto-Aztecan people of southern Arizona and northern Sonora, and the language they speak.

Oahu

The third-largest island in Hawaii, home to Honolulu and the majority of the state’s population.

Oak

A large tree of the beech family with lobed leaves and acorns, valued for its hard wood.

Oar

A long pole with a flat blade used to row or steer a boat.

Oat

A cereal plant cultivated for its edible grains, commonly used as food for humans and livestock.

Oath

A solemn promise, often invoking a divine witness, regarding one's future action or behavior.

Oathbound

Bound or obligated by an oath or promise.

Oathbreaker

A person who breaks a sworn promise or oath.

Oathkeeper

A person who keeps or honors an oath.

Oathsworn

Bound or pledged by a solemn oath, especially to a person, cause, or code.

Oaxaca

A state in southern Mexico, and its capital city, known for its Indigenous cultures and rich regional history.

Obadiah

A biblical Hebrew name meaning “servant of Yahweh,” borne by several figures in the Hebrew Bible.

Obdormition

The state of being asleep or in a deep sleep.

Obduction

The action of drawing over or covering something.

Obdurate

Stubbornly refusing to change one’s opinion or course of action.

Obedient

Willing to comply with authority, rules, or instructions.

Obelia

A genus of colonial hydrozoans, often forming delicate branching marine colonies.

Obelion

A point on the skull near the posterior fontanelle, used in craniometry.