| phantom | That which has only an apparent existence; an apparition; a specter; a phantasm; a sprite; an airy spirit; an ideal image. "Strange phantoms rising as the mists arise." (Pope) "She was a phantom of delight." (Wordsworth) Phantom ship. See Flying Dutchman, under Flying. <medicine> Phantom tumour, a swelling, especially of the abdomen, due to muscular spasm, accumulation of flatus, etc, simulating an actual tumour in appearance, but disappearing upon the administration of an anaesthetic. Origin: OE. Fantome, fantosme, fantesme, OF. Fantome, fr. L. Phantasma, Gr, fr. To show. See Fancy, and cf. Phaeton, Phantasm, Phase. Source: Websters Dictionary (01 Mar 1998) |
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| phantom aneurysm | A palpable throbbing aorta, mistaken by novices for an aneurysm. (05 Mar 2000) |
| phantom corpuscle | A hypochromic, crescent-shaped erythrocyte, probably resulting from artifactual rupture of a red cell with loss of haemoglobin. Synonym: achromacyte, achromatocyte, ghost corpuscle, phantom corpuscle, Ponfick's shadow, shadow corpuscle, shadow, Traube's corpuscle. Origin: G. A-priv. + chroma, colour, + kytos, hollow (cell) (05 Mar 2000) |
| phantom limb | The sensation, after amputation of a limb, that the absent part is still present; there may also be paresthesias, transient aches, and intermittent or continuous pain perceived as originating in the absent limb. (12 Dec 1998) |
| phantom limb pain | The sensation, after amputation of a limb, that the absent part is still present; there may also be paresthesias, transient aches, and intermittent or continuous pain perceived as originating in the absent limb. (12 Dec 1998) |
| phantom pregnancy | An obsolete term for false pregnancy. (05 Mar 2000) |
| phantom tumour | Accumulation of fluid in the interlobar spaces of the lung, secondary to congestive heart failure, radiologically simulating a neoplasm. (05 Mar 2000) |
| Schultze's phantom | A model of a female pelvis used in demonstrating the mechanism of childbirth and the application of forceps. (05 Mar 2000) |
| acoustic reference level | The biological reference level for sound measurements. When the term decibel is used to indicate the noise level, a reference quantity is implied; this reference value is usually expressed as a sound pressure of 20 micronewtons per square meter. The reference level is referred to as 0 decibels, the baseline of the scale of noise level's; this baseline is considered the weakest sound that can be heard by a person with very good hearing in an extremely quiet location. Other equivalent reference level's still being used include 0.0002 microbar and 0.0002 dyne per square centimeter. (05 Mar 2000) |
| reference | The act of referring or consulting, something that refers to something else. (18 Nov 1997) |
| reference books | Books designed by the arrangement and treatment of their subject matter to be consulted for definite terms of information rather than to be read consecutively. Reference books include dictionaries, encyclopedias, atlases, etc. (12 Dec 1998) |
| reference books, medical | Books in the field of medicine intended primarily for consultation. (12 Dec 1998) |
| reference electrode | An electrode expected to have a constant potential, such as a calomel electrode, and used with another electrode to complete an electrical circuit through a solution; e.g., when a reference electrode is used with a glass electrode for pH measurement, changes in voltage between the two electrode's can be attributed to the effects of pH on the glass electrode alone. (05 Mar 2000) |
| reference method | An analytical procedure sufficiently free of random or systematic error to make it useful for validating proposed new analytical procedures for the same analyte. (05 Mar 2000) |
| reference standards | A basis of value established for the measure of quantity, weight, extent or quality, e.g. Weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy. (12 Dec 1998) |