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acrylonitrile a poisonous and carcinogenic liquid that is made into polymers for use as raw material in acrylic fibers.
act something done, esp. a specific instance; deed. [14 definitions]
actable capable of being acted, as a role or a play.
ACTH a hormone produced by the anterior pituitary that stimulates the cortex of the adrenal gland to produce cortisone and other hormones; adrenocorticotropic hormone.
actin any of a group of contractile proteins, including proteins involved in muscle contraction, cell motility, and maintenance of cellular shape.
acting appointed as a temporary substitute for someone absent from an office or position; serving temporarily. [5 definitions]
actinic of or pertaining to the chemical property of ultraviolet radiation and x-rays that produces photochemical effects.
actinic rays electromagnetic radiation, such as x-rays or ultraviolet light, that can produce an image on a photographic emulsion.
actinide any of the chemical elements of the actinide series.
actinide series the series of chemical elements, mostly synthetic and all radioactive, that have from eighty-nine to 103 protons per atom.
actinism the property of radiation that produces chemical activity.
actinium a radioactive chemical element of the rare-earth group that has eighty-nine protons in each nucleus. (symbol: Ac)
actinogen any of the radioactive chemical elements.
actinoid having a radial or star-shaped form, as certain sea creatures.
actinomycin any of several antibiotics derived from soil bacteria that work against certain other bacteria and fungi.
actinomycosis an infectious disease of animals and humans that is caused by parasites and produces abscesses, esp. in the jaws.
actinozoan see anthozoan.
action something that is done, is being done, or will be done. [8 definitions]
actionable providing legitimate grounds for legal action.
action-adventure a genre of films, video games, and the like having an exciting undertaking involving risk and danger as its main story line, and involving one or more heroes engaged in a series of physical challenges. [2 definitions]
actionless combined form of action.