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Acrylic

A paint in which the pigment is suspended in a solution of an acrylic resin, which dries to a hard film on exposure to air.

Acrylic resin

a thermoplastic made by polymerization of acrylic acid or methacrylic acid or some derivative of these (such as the esters or amides). It can be formed into a clear hard plastic, and is the basis for the commercial plastics called Lucite and Plexiglass.

acrylonitrile

a colorless liquid compound (H2C:CH.CN); used as raw material for acrylic fibers, and as a solvent.

Act

To exert power; to produce an effect; as, the stomach acts upon food.

ACTH

a growth hormone produced by the anterior pituitary gland; stimulates the adrenal cortex.

Actinal

Pertaining to the part of a radiate animal which contains the mouth.

Actinaria

An order of Anthozoa, including those which have simple tentacles and do not form stony corals. Sometimes, in a wider sense, applied to all the Anthozoa, expert the Alcyonaria, whether forming corals or not.

Actinia

An animal of the class Anthozoa, and family Actinid/. From a resemblance to flowers in form and color, they are often called animal flowers and sea anemones. [See Polyp.]. A genus in the family Actinid/.

actinian

any sea anemone or related animal.

Actinic

Of or pertaining to actinism; as, actinic rays.

Actinidia

a small Asiatic woody vine bearing many-seeded fruit.

Actiniform

Having a radiated form, like a sea anemone.

Actiniopteris

a genus of terrestrial ferns of tropical Asia and Africa.

Actinism

The property of radiant energy (found chiefly in solar or electric light) by which chemical changes are produced, as in photography.

Actinium

A supposed metal, said by Phipson to be contained in commercial zinc; -- so called because certain of its compounds are darkened by exposure to light.

Actinograph

An instrument for measuring and recording the variations in the actinic or chemical force of rays of light.

Actinoid

Having the form of rays; radiated, as an actinia.

Actinolite

A bright green variety of amphibole occurring usually in fibrous or columnar masses.

Actinolitic

Of the nature of, or containing, actinolite.

Actinology

The science which treats of rays of light, especially of the actinic or chemical rays.

Actinomere

One of the radial segments composing the body of one of the C/lenterata.

Actinometer

An instrument for measuring the direct heating power of the sun's rays. An instrument for measuring the actinic effect of rays of light.

Actinometric

Pertaining to the measurement of the intensity of the solar rays, either (a) heating, or (b) actinic.

Actinometry

The measurement of the force of solar radiation.

actinomycetes

branched gram-positive bacteria, often found in soil, some of which are pathogenic for humans and animals.

actinomycin

any of various red antibiotics isolated from soil bacteria with a three-ring heterocyclic nucleus with an attached peptide chain.

actinomycin D

The most well-known of the actinomycins (C62H86N12O16), a class of antibiotics which act by binding to DNA and inhibiting synthesis of RNA; they act agains gram-positive bacteria and many eukaryotic organisma. Actinomycin D has been used in human medicine to treat certain tumors.

Actinomycosis

A chronic infectious disease of cattle and man due to infection with actinomycetes, especially by Actinomyces bovis in cattle and by Actinomyces israeli or Arachnia propionica in man. It is characterized by hard swellings usually in the mouth and jaw. In man the disease may also affect the abdomen or thorax. In cattle it is called also lumpy jaw or big jaw.

Actinophone

An apparatus for the production of sound by the action of the actinic, or ultraviolet, rays.

Actinophonic

Pertaining to, or causing the production of, sound by means of the actinic, or ultraviolet, rays; as, actinophonic phenomena.

actinopod

protozoa having stiff rodlike radiating pseudopods.

Actinost

One of the bones at the base of a paired fin of a fish.

Actinostome

The mouth or anterior opening of a c/lenterate animal.

Actinotrocha

A peculiar larval form of Phoronis, a genus of marine worms, having a circle of ciliated tentacles.

Actinozoa

A group of C/lenterata, comprising the Anthozoa and Ctenophora. The sea anemone, or actinia, is a familiar example.

Actinula

A kind of embryo of certain hydroids (Tubularia), having a stellate form.

Action

A process or condition of acting or moving, as opposed to rest; the doing of something; exertion of power or force, as when one body acts on another; the effect of power exerted on one body by another; agency; activity; operation; as, the action of heat; a man of action.

Actionable

That may be the subject of an action or suit at law; as, to call a man a thief is actionable.

Actium

naval battle where Antony and Cleopatra were defeated by Octavian's fleet under Agrippa in 31 BC.

activated

treated with aeration and bacteria to aid decomposition; -- of sewage

activation

the process of making active. making active and effective (as a bomb).

activator

any agency bringing about activation; (Biol.) a molecule that increases the activity of an enzyme or a protein that increases the production of a gene product in DNA transcription.

Active

Having the power or quality of acting; causing change; communicating action or motion; acting; -- opposed to passive, that receives; as, certain active principles; the powers of the mind.

Actively

In an active manner; nimbly; briskly; energetically; also, by one's own action; voluntarily, not passively.

Activeness

The quality of being active; nimbleness; quickness of motion; activity.

activism

a policy of taking direct and militant action to achieve a political or social goal.

activist

one who is aggressively active on behalf of a cause.

Activity

The state or quality of being active; nimbleness; agility; vigorous action or operation; energy; active force; as, an increasing variety of human activities.

Acton

A stuffed jacket worn under the mail, or (later) a jacket plated with mail.

Actor

One who acts, or takes part in any affair; a doer.

Acts

one of the books of the Christian New Testament describing the activities of Christ's apostles after his death.

Actual

Something actually received; real, as distinct from estimated, receipts.

Actualist

One who deals with or considers actually existing facts and conditions, rather than fancies or theories; a realist; -- opposed to idealist.

Actuality

The state of being actual; reality; as, the actuality of God's nature.

Actualize

To make actual; to realize in action.

actualized

changed from potential to actual; as, saw his worst fears actualized.

Actuarial

Of or pertaining to actuaries; as, the actuarial value of an annuity.

Actuary

A registrar or clerk; -- used originally in courts of civil law jurisdiction, but in Europe used for a clerk or registrar generally.

Actuator

One who actuates, or puts into action.

Acuate

Sharpened; sharp-pointed.

Acuity

Sharpness or acuteness, as of a needle, wit, etc.

Aculea

A small spiny outgrowth on the wings of certain insects.

Aculeate

Having a sting; covered with prickles; sharp like a prickle.

Aculeated

Having a sharp point; armed with prickles; prickly; aculeate.

Aculeus

A prickle growing on the bark, as in some brambles and roses.

Acumen

Quickness of perception or discernment; penetration of mind; the faculty of nice discrimination.

Acuminate

To end in, or come to, a sharp point.

Acumination

A sharpening; termination in a sharp point; a tapering point.

Acupressure

A mode of arresting hemorrhage resulting from wounds or surgical operations, by passing under the divided vessel a needle, the ends of which are left exposed externally on the cutaneous surface.

Acute

To give an acute sound to; as, he acutes his rising inflection too much.

Acute-angled

Having acute angles; as, an acute-angled triangle, a triangle with every one of its angles less than a right angle.

Acutely

In an acute manner; sharply; keenly; with nice discrimination.

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