English words starting with O

The quality of being willing to consider new ideas and opinions that are different from your own.

Having one's mouth wide open, especially in surprise, shock, or awe.

(of a shirt or blouse) having the neck open at the front, not fastened with buttons or a tie.

Relating to or being a mine or excavation in which the work is done from an open surface, not from underground shafts.

Describing a room or building in which there are few or no walls dividing the space.

(of a plant) fertilized by pollen carried by wind, insects, birds, or other natural means from any other plant of the same species, rather than by controlled human intervention.

Having one or more sides that are not enclosed or are left open.

Denoting software for which the original source code is made freely available and may be redistributed and modified.

An area of land that is not built on, especially one used for recreation or as part of a development.

(of a shoe or sandal) having the front part of the foot exposed; not covering the toes.

Having a roof that can be folded back or removed.

Having no roof or cover on top.

Taking place in or relating to an area of sea, lake, or river that is away from the shore.

(of a racing car) having the wheels outside the main body of the vehicle and not enclosed by bodywork.

Not closed or sealed; allowing access

A device or tool used to open something, such as a can or bottle.

a hole or empty space that allows passage or access

the first day of a new season, especially for a sporting competition or a public event

the first game in a series or tournament.

The first public performance of a play, film, or other show.

the first game, match, or stage in a competition or tournament

In a way that makes no attempt to hide one's thoughts, feelings, or actions; frankly or publicly.

the quality of being willing to accept new ideas, people, or things; a lack of secrecy or concealment.

Ornamental work in cloth, metal, leather, etc., with patterns of openings and holes.

A dramatic work in which all or most of the text is sung to orchestral accompaniment, typically involving elaborate costumes and scenery.

The quality or state of being able to be used, operated, or function effectively.

Able to be used or in working order.

A quantity or piece of data on which an operation is performed.

(of an action) producing or influencing a result or effect.

to function or cause to function; to work.

Relating to or characteristic of opera.

Functioning or in action.

A room in a hospital where surgical operations are performed.

The main software that controls a computer and makes it possible for other programs to function.

The fact or process of working, being active, or functioning.

Relating to the functioning or active use of something, rather than theory or planning.

the process of defining a concept or variable so that it can be measured or manipulated in a practical way.

To put something into operation or use; to make something functional or effective.

In a way that relates to the functioning or active use of something

In or ready for use; functioning effectively.

a person who operates equipment or a machine

a short, usually humorous opera with a light, romantic story and spoken dialogue.

relating to the eye or the sense of sight.

relating to the branch of medicine concerned with the study and treatment of disorders and diseases of the eye.

a doctor who specializes in the study and treatment of diseases and injuries of the eye.

the scientific study of the eye and its diseases

a drug that contains opium, used to reduce pain or help someone sleep

to express an opinion

A belief or judgment about something, not necessarily based on fact or knowledge.

holding very strong opinions that you are unwilling to change

Any of a group of natural or synthetic compounds that act on opioid receptors in the brain to produce effects like those of morphine.

a powerful drug made from the juice of a type of poppy, used in the past in medicines to reduce pain and help people sleep.

a small american marsupial with a pointed snout and a hairless, prehensile tail, noted for feigning death when threatened.

a person who competes against or fights another in a contest, game, or argument; a rival or adversary.

(of a time) especially convenient or appropriate for a particular action or event.

the practice of taking advantage of opportunities as they arise, especially with little regard for principles or consequences.

A person who takes advantage of opportunities as and when they arise, especially with little regard for principles or consequences.

exploiting immediate opportunities, especially in a selfish or unprincipled way.

In a manner that takes advantage of opportunities as and when they arise, especially with little regard for principles or consequences.

a time or set of circumstances that makes it possible to do something.

(of the thumb) capable of being placed against the fingers of the same hand, enabling grasping and holding

to disagree strongly with or try to stop a plan, policy, person, or system

Disagreeing with or resisting something; in conflict or competition with.

in conflict or competition with someone or something

completely different; facing or moving away from each other

(In baseball and softball) a batted ball hit to the side of the field opposite the batter's natural batting stance (i.e., a right-handed batter hitting to right field, or a left-handed batter hitting to left field).

Of, relating to, or being the other of the two sexes or genders, especially when considered in relation to each other.

Relating to or characteristic of the other gender.

in a manner that is completely different or contrary in position, direction, or meaning.

strong disagreement with, or protest against, something such as a plan, law, or system

Relating to or characterized by opposition, resistance, or antagonism.

A person who opposes or is in opposition, especially to a government or political system.

To govern or treat people in a cruel and unfair way, not allowing them the same rights, freedom, and benefits as others.

Treated in a cruel and unfair way and not given the same freedom, rights, or opportunities as other people.

The cruel and unfair treatment of people, especially by not giving them the same freedom, rights, etc. as other people.

using power or authority in a cruel and unfair way

in a cruel and unfair way that limits freedom

The quality of making people feel heavily burdened, mentally or physically, by being cruel, unjust, or by creating a harsh, uncomfortable atmosphere.

A person or group that uses power or authority in a cruel and unfair way to control other people.

expressing severe criticism or scorn; conveying disgrace or shame.

Harsh criticism or strong disapproval, often accompanied by a loss of respect and public shame.

To make a choice or decision from a range of possibilities.

an instance of choosing not to participate in something

Relating to the eye or vision.

Relating to vision, sight, or light.

In a way that relates to sight, light, or the use of lenses and other visual devices.

A person who is qualified to make and supply eyeglasses and contact lenses for correcting vision, as prescribed by an optometrist or ophthalmologist.

The scientific study of sight and the behavior of light, or the properties of lenses and other devices that use light.

Best or most favorable; most desirable or satisfactory under the given circumstances.

in the best or most effective way possible

a feeling that good things will happen and that something will be successful; the tendency to have this feeling

a person who tends to be hopeful and confident about the future or the success of something.

hopeful and confident about the future

in a way that shows hope and confidence about the future

The process of making something as good or as effective as possible.

to make something as good or as effective as possible.

Made as perfect or effective as possible.

(present participle) To make something as good, effective, or functional as possible.

The most favorable or best possible condition, amount, or degree for a particular situation.

something that you can choose to have or do; the freedom to choose what you do

Available to be chosen but not compulsory.

In a way that is available to be chosen but is not obligatory.

Relating to or involving devices that function using both light and electricity.

A person whose job is to examine people's eyes and to recommend and sell glasses and contact lenses.

The profession of examining the eyes to measure vision and prescribe corrective lenses.

Great wealth or luxuriousness.

having or showing great wealth; luxurious or lavish.

A musical composition or set of compositions by a particular composer, numbered to show the order of publication or composition.

used to link alternatives

(in ancient Greece) a priest or priestess acting as a medium through whom advice or prophecy was sought from the gods.

Relating to or resembling an oracle; mysterious and difficult to interpret.

Relating to the mouth.

By means of speech; spoken rather than written.

A large, intelligent ape with long arms and reddish-brown hair, native to the rainforests of Borneo and Sumatra.

A round, juicy citrus fruit with a tough, bright reddish-yellow skin

Having the colors orange and black, especially in a pattern or combination.

of a color that is a mixture of orange and brown.

having the color of an orange; a shade between red and yellow.

Having the taste or smell of an orange.

Having hair that is the color of an orange; having red or ginger hair.