| AAS | Aarskog-Scott [syndrome]; acid aspiration syndrome; alcoholic abstinence syndrome; American Academy ... |
|---|---|
| ABC | absolute basophil count; absolute bone conduction; acalculous biliary colic; acid balance control; a... |
| ABCC | Atomic Bomb Casualty Commission |
| AEC | ankyloblepharon, ectodermal defects, and cleft lip [syndrome]; at earliest convenience; Atomic Energ... |
| AEE | atomic energy establishment |
| Becquerel rays | An obsolete term for radiations given off by uranium and other radioactive substances; these include alpha, beta, and gamma ray's. (05 Mar 2000) |
|---|---|
| gamma rays | Very powerful and penetrating, high-energy electromagnetic radiation of shorter wavelength than that of X-rays. They are emitted by a decaying nucleus, usually between 0.01 and 10 mev. They are also called nuclear X-rays. (12 Dec 1998) |
| parallel rays | Ray's parallel to the axis of an optical system. (05 Mar 2000) |
| marginal rays | In geometric optics, those ray's originating from the periphery. (05 Mar 2000) |
| paraxial rays | In geometric optics, those ray's focused at the principal point. (05 Mar 2000) |
| cathode rays | A stream of electrons emitted from the negative electrode (cathode) in a Crookes tube; their bombardment of the anode or the glass wall of the tube gives rise to X-ray's. (05 Mar 2000) |
| glass rays | Those formed by cathode ray's striking the wall of an X-ray tube. (05 Mar 2000) |
| cephalometric X-rays | <dentistry> An X-ray of the head that shows whether your teeth are aligned properly, and whether they are growing properly. (08 Jan 1998) |
| monochromatic rays | Light ray's or ionizing radiation of a very narrow band of wavelengths (ideally, of a single wavelength). Compare: photopeak, characteristic radiation. (05 Mar 2000) |
| W rays | Those between ultraviolet and X-ray's. Synonym: W rays. (05 Mar 2000) |
| cosmic rays | <radiobiology> High velocity particles of enormous energies, bombarding earth from outer space. It consists of protons and more complex atomic nuclei that, on striking the atmosphere, give rise to neutrons, mesons, and other less energetic radiation. (05 Mar 2000) |
| positive rays | Those originating in a gas discharge tube and moving in a direction opposite to that of cathode ray's; made up of positively charged ions. Synonym: positive rays. (05 Mar 2000) |
| hard rays | Ray's of short wavelength and great penetrability. (05 Mar 2000) |
| primary rays | Cosmic ray's in the form in which they first strike the atmosphere, X-ray's generated at the focal spot of the tube. Synonym: direct rays. (05 Mar 2000) |
| X-rays | Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release energy - in the same energy range as gamma rays (0.010-10 mev), but of non-nuclear origin, of shorter wavelength than ultraviolet; soft X-rays or grenz rays are less penetrating and longer in wavelength than hard X-rays. (12 Dec 1998) |