| acromegaly |
a chronic disease causing abnormal enlargement of the hands, feet, and parts of the face, usu. caused by a tumor of the pituitary gland. |
| acronym |
a type of abbreviation used as a word, formed by combining the initial letters (or initial parts) of words that make up a particular string. The pronunciation of an acronym is based on the typical rules of pronouncing words in a language and is not made up of the sounds of the names of individual letters. |
| acrophobia |
an overwhelming fear of high places. |
| acropolis |
a fortified hill of an ancient Greek city. [2 definitions] |
| across |
from one side or end to the other of. [7 definitions] |
| across the board |
applying equally to all parts or members. |
| acrostic |
a sequence of written lines in which particular letters, usu. the first letter of every line, form an independent word or phrase. [2 definitions] |
| acrylic |
of or characteristic of the corrosive liquid, acrylic acid. [2 definitions] |
| acrylic fiber |
any of a group of synthetic fibers that are made chiefly of acrylonitrile that has been formed into polymers. |
| acrylic resin |
any of a group of transparent synthetic resins that become pliable or set when heated and are used in acrylic fibers, plastics, and synthetic rubbers. |
| 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. |
| 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) |