| AGA | accelerated growth area; allergic granulomatosis and angiitis; American Gastroenterological Associat... |
|---|---|
| AHEA | area health education activity |
| AHEC | area health education center |
| AHPO | anterior hypothalamic preoptic [area] |
| AHS | Academy of Health Sciences; African horse sickness; alveolar hypoventilation syndrome; American Hear... |
| secondary vitreous | Avascular vitreous formed around the primary vitreous. (05 Mar 2000) |
|---|---|
| secondary wall | <plant biology> The part of the plant cell wall which is laid down on top of the primary wall after the wall has ceased to increase in surface area. Only occurs in certain cell types, for example tracheids, vessel elements and sclerenchyma. Differs from the primary wall both in composition and structure and is often diagnostic for a particular cell type. (18 Nov 1997) |
| secondary X zone | An adrenocortical zone, situated in the inner zona fasciculata, that appears upon postpubertal gonadectomy in some male rodents, most notably the mouse; the development of this zone is believed to be stimulated by pituitary gonadotropins. (05 Mar 2000) |
| spectrometry, mass, secondary ion | A mass-spectrometric technique that is used for microscopic chemical analysis. A beam of primary ions with an energy of 5-20 kiloelectronvolts (kev) bombards a small spot on the surface of the sample under ultra-high vacuum conditions. Positive and negative secondary ions sputtered from the surface are analyzed in a mass spectrometer in regards to their mass-to-charge ratio. (12 Dec 1998) |
| dentin, secondary | Dentin formed and deposited in response to a normal or slightly abnormal stimulus, after the complete formation of the tooth. (12 Dec 1998) |
| immunization, secondary | Any immunization following a primary immunization and involving exposure to the same or a closely related antigen. (12 Dec 1998) |
| osteoarthropathy, secondary hypertrophic | Symmetrical osteitis of the four limbs, chiefly localised to the phalanges and the terminal epiphyses of the long bones of the forearm and leg, sometimes extending to the proximal ends of the limbs and the flat bones, and accompanied by dorsal kyphosis and joint involvement. It is often secondary to chronic conditions of the lungs and heart. (12 Dec 1998) |
| acoustic area | The floor of the lateral recess of the fourth ventricle, extending medially to the limiting sulcus and overlying the cochlear and vestibular nuclei of the rhombencephalon. Synonym: area acustica. (05 Mar 2000) |
| adaptive management area | Landscape units designated for development and testing of technical and social approaches to achieving desired ecological, economic, and other social objectives. (05 Dec 1998) |
| air quality maintenance area | Specific populated area where air quality is a problem for one or more pollutants (Portland-Vancouver, Salem, Eugene-Springfield, Medford-Ashland). (05 Dec 1998) |
| anterior intercondylar area of tibia | The broad depressed area between the tibial condyles anteriorly to which attach the anterior ends of the menisci and the anterior cruciate ligament. Synonym: area intercondylaris anterior tibiae. (05 Mar 2000) |
| aortic area | The region of the chest wall over the second right costal cartilage, where sounds produced at the aortic orifice are often best heard. (05 Mar 2000) |
| apical area | The area about the root end of a tooth. (05 Mar 2000) |
| area | Origin: L. Area a broad piece of level gro. Cf. Are. 1. Any plane surface, as of the floor of a room or church, or of the ground within an inclosure; an open space in a building. "The Alban lake . . . Looks like the area of some vast amphitheater." (Addison) 2. The inclosed space on which a building stands. 3. The sunken space or court, giving ingress and affording light to the basement of a building. 4. An extent of surface; a tract of the earth's surface; a region; as, vast uncultivated areas. 5. <geometry> The superficial contents of any figure; the surface included within any given lines; superficial extent; as, the area of a square or a triangle. 6. <biology> A spot or small marked space; as, the germinative area. 7. Extent; scope; range; as, a wide area of thought. "The largest area of human history and man's common nature." (F. Harrison) Dry area. See Dry. Source: Websters Dictionary (01 Mar 1998) |
| area acustica | The floor of the lateral recess of the fourth ventricle, extending medially to the limiting sulcus and overlying the cochlear and vestibular nuclei of the rhombencephalon. Synonym: area acustica. (05 Mar 2000) |