The act or process of operating; agency; the exertion of power, physical, mechanical, or moral.

of or pertaining to operations; as, operational procedure.

the doctrine that the meaning of a proposition consists of the operations involved in defining, proving, or applying it.

Of or pertaining to operationalism.

financial transactions at a brokerage; having to do with the execution of trades and keeping customer records.

A skilled worker; an artisan; esp., one who operates a machine in a mill or manufactory.

In an operative manner.

One who, or that which, operates or produces an effect.

A laboratory.

Any one of the bony plates which support the gill covers of fishes; an opercular bone.

See Operculum.

The principal opercular bone or operculum of fishes.

Closed by a lid or cover, as the capsules of the mosses.

Bearing an operculum.

Having the form of a lid or cover.

Producing an operculum; -- said of the foot, or part of the foot, of certain mollusks.

The lid of a pitcherform leaf. The lid of the urnlike capsule of mosses.

A short, light, musical drama.

Wrought with labor; requiring labor; hence, tedious; wearisome.

Laboriousness.

Operose.

Concealed; private.

Open time; -- applied to different things The early spring, or the time when flowers begin opening. The time between Epiphany and Ash Wednesday wherein marriages were formerly solemnized publicly in churches. The time after harvest when the common fields are open to all kinds of stock.

Of, pertaining to, or designating, a substance (called ophelic acid) extracted from a plant (Ophelia) of the Gentian family as a bitter yellowish sirup, used in India as a febrifuge and tonic.

A large brass wind instrument, formerly used in the orchestra and in military bands, having a loud tone, deep pitch, and a compass of three octaves; -- now generally supplanted by bass and contrabass tubas. It developed from the older wooden instrument called the serpent.

The suborder of reptiles which includes the serpents; called also Serpentes.

Of or pertaining to the Ophidia; belonging to serpents.

Of or pertaining to the Ophidiidae, a family of fishes which includes many slender species. One of the Ophidiidae.

The typical genus of ophidioid fishes. [Written also Ophidium.] See Illust. under Ophidioid.

Ophidian.

A natural family of fishes closely related to greenlings (fish of the genus Hexagrammos).

A natural family of succulent ferns cosmopolitan in distribution.

An order coextensive with the family Ophioglossaceae.

The worship of serpents.

Of or pertaining to ophiology.

One versed in the natural history of serpents.

That part of natural history which treats of the ophidians, or serpents.

Divination by serpents, as by their manner of eating, or by their coils.

An order of tailless amphibians having a slender, wormlike body with regular annulations, and usually with minute scales imbedded in the skin. The limbs are rudimentary or lacking. It includes the caecilians. Called also Gymnophiona and Ophidobatrachia.

An ammonite.

Having the form of a serpent.

Feeding on serpents; -- said of certain birds and reptiles.

A genus of venomous East Indian snakes, which feed on other snakes. Ophiophagus elaps is said to be the largest and most deadly of poisonous snakes.

Doctrines and rites of the Ophites.

A mamber of a Gnostic serpent-worshiping sect of the second century.

A constellation in the Northern Hemisphere, delineated as a man holding a serpent in his hands; -- called also Serpentarius.

A genus of ophiurioid starfishes.

Of or pertaining to the Ophiurioidea. One of the Ophiurioidea.

Same as Ophiurioid.

Same as Ophiurioidea.

Of or pertaining to the Ophiurioidea. One of the Ophiurioidea.

A class of star-shaped echinoderms having a disklike body, with slender, articulated arms, which are not grooved beneath and are often very fragile; -- called also Ophiuroida and Ophiuridea. See Illust. under Brittle star.

The supraorbital point.

An inflammation of the membranes or coats of the eye or of the eyeball.

Of, pertaining to, or in the region of, the eye; ocular; as the ophthalmic, or orbitonasal, nerve, a division of the trigeminal, which gives branches to the lachrymal gland, eyelids, nose, and forehead.

An eyestalk; the organ which bears the compound eyes of decapod Crustacea.

severe conjunctivitis; ophthalmia.

Of or pertaining to ophthalmology.

One skilled in ophthalmology; an oculist.

The science which treats of the structure, functions, and diseases of the eye.

An instrument for viewing the interior of the eye, particularly the retina. Light is thrown into the eye by a mirror (usually concave) and the interior is then examined with or without the aid of a lens.

A branch of physiognomy which deduces the knowledge of a person's temper and character from the appearance of the eyes.

Same as Ophthalmia.

Of, pertaining to, or designating, an organic acid obtained by the oxidation of narcotine.

An alkaloid (C22H23NO7) found in small quantity in opium. It is identical with narcotine. It is present in amounts up to 11% in Papaver somniferum, and is used clinically as an antitussive.

Same as Meconin.

To subject to the influence of an opiate; to put to sleep.

Mixed with opiates.

Opium.

Bringing help.

Workmanship.

An artificer; a workman.

Capable of being opined or thought.

The act of thinking; a supposition.

Obstinate in holding opinions; opinionated.

One fond of his own opinions; one who holds an opinion.

To have an opinion; to judge; to think; to suppose.

One who opines.

See Opiniaster. [Obs.].

To hold or maintain persistently.

Opinionated.

Opinionative.

See Opiniaster.

Opinionated.

One who is opinionated.

Obstinacy in opinions.

An imaginary animal borne as a charge, having wings, an eagle's head, and a short tail; -- sometimes represented without wings.

Opinion.

To opine.

Being, or capable of being, a matter of opinion; that can be thought; not positively settled; as, an opinionable doctrine.

Opinionated.

Stiff in opinion; firmly or unduly adhering to one's own opinion or to preconceived notions; obstinate in opinion.

Conceitedly.

An opinionist.

Unduly attached to one's own opinions; opinionated.

An opinionated person; one given to conjecture.

Opinionated; conceited.

One fond of his own notions, or unduly attached to his own opinions.

Sumptuous.

An instrument with a revolving wheel for measuring a curved line, as on a map.

The middle of the posterior, or dorsal, margin of the great foramen of the skull.

A division of gastropod Mollusca, in which the breathing organs are usually situated behind the heart. It includes the tectibranchs and nudibranchs.

Of or pertaining to the Opisthobranchiata. One of the Opisthobranchiata.

Concave behind; -- applied especially to vertebrae in which the anterior end of the centrum is convex and the posterior concave.

A back chamber; especially, that part of the naos, or cella, farthest from the main entrance, sometimes having an entrance of its own, and often used as a treasury.

A division of serpents which have some of the posterior maxillary teeth grooved for fangs.

A writing upon the back of anything, as upon the back of a leaf or sheet already written upon on one side.

An order of eellike fishes having the scapular arch attached to the vertebrae, but not connected with the skull.

Having the pulmonary sac situated posteriorly; -- said of certain air-breathing Mollusca.

The inferior and posterior of the three elements forming the periotic bone.

A tetanic spasm in which the body is bent backwards and stiffened.

The act of helping or aiding; help.

The inspissated juice of the Papaver somniferum, or white poppy.

The old name of the aromatic resinous juice of the Balsamodendron opobalsamum, now commonly called balm of Gilead. See under Balm.

A kind of plaster, said to have been invented by Mindererus, -- used for external injuries.

See Army organization, above.

The inspissated juice of an umbelliferous plant (the Opoponax Chironum), brought from Turkey and the East Indies in loose granules, or sometimes in larger masses, of a reddish yellow color, with specks of white. It has a strong smell and acrid taste, and was formerly used in medicine as an emmenagogue and antispasmodic.

Any American marsupial of the genera Didelphys and Chironectes; called also possum. The common species of the United States is Didelphys Virginiana.

An older division of the suborder Ophidia of serpents; it includes those snakes in which the mouth is not dilatable.

An inhabitant of a town.