| vacuole | <cell biology> Membrane bounded vesicle of eukaryotic cells. Secretory, endocytotic and phagocytotic vesicles can be termed vacuoles. Botanists tend to confine the term to the large vesicles found in plant cells that provide both storage and space filling functions. (18 Nov 1997) |
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| vacuoles | Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion. (12 Dec 1998) |
| vacuolization | <biology> Formation into, or multiplication of, vacuoles. Source: Websters Dictionary (01 Mar 1998) |
| vacuome | A system of vacuoles that can be stained with neutral red in the living cell. Origin: vacuole + G. -oma, tumour (05 Mar 2000) |
| vacuous | Empty; unfilled; void; vacant. "Boundless the deep, because I am who fill Infinitude; nor vacuous the space." (Milton) "That the few may lead selfish and vacuous days." (J. Morley) Origin: L. Vacuus. See Vacant. Source: Websters Dictionary (01 Mar 1998) |
| vacutome | Electrodermatome that applies suction to the skin to raise it before an advancing blade, usually for taking a split-thickness skin graft. Origin: vacuum + G. Tome, a cutting (05 Mar 2000) |
| vacuum | Origin: L, fr. Vacuus empty. See Vacuous. 1. <physics> A space entirely devoid of matter (called also, by way of distinction, absolute vacuum); hence, in a more general sense, a space, as the interior of a closed vessel, which has been exhausted to a high or the highest degree by an air pump or other artificial means; as, water boils at a reduced temperature in a vacuum. 2. The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, as the condenser of a steam engine, which is nearly exhausted of air or steam, etc.; as, a vacuum of 26 inches of mercury, or 13 pounds per square inch. Vacuum brake, a kind of continuous brake operated by exhausting the air from some appliance under each car, and so causing the pressure of the atmosphere to apply the brakes. <medicine> Vacuum pan, a glass tube provided with platinum electrodes and exhausted, for the passage of the electrical discharge; a Geissler tube. Vacuum valve, a safety valve opening inward to admit air to a vessel in which the pressure is less than that of the atmosphere, in order to prevent collapse. Torricellian vacuum. See Torricellian. Source: Websters Dictionary (01 Mar 1998) |
| vacuum casting | The casting of a metal in the presence of a vacuum. (05 Mar 2000) |
| vacuum curettage | Aspiration of the contents of the uterus with a vacuum curette. (12 Dec 1998) |
| vacuum desiccator | A desiccator that can be evacuated. (05 Mar 2000) |
| vacuum disk phenomenon | The appearance of a radiolucent stripe in an intervertebral disk, a manifestation of disk degeneration; a misnomer since there is gas present. (05 Mar 2000) |
| vacuum extraction, obstetrical | Removal of the foetus from the uterus or vagina at or near the end of pregnancy with a metal traction cup that is attached to the foetus' head. Negative pressure is applied and traction is made on a chain passed through the suction tube. (12 Dec 1998) |
| vacuum extractor | Device for producing traction upon the head of a foetus by means of a soft cup held by a vacuum. (05 Mar 2000) |
| vacuum flask | <apparatus> A glass vessel, often silvered, with two walls, the space between which is evacuated; used for maintaining materials at constant temperature or, more usually, at low temperature. Synonym: vacuum flask. (05 Mar 2000) |
| vacuum headache | Headache due to closure of the frontal sinus. (05 Mar 2000) |