| hour | 1. <physics> The twenty-fourth part of a day; sixty minutes. 2. The time of the day, as expressed in hours and minutes, and indicated by a timepiece; as, what is the hour? at what hour shall we meet? 3. Fixed or appointed time; conjuncture; a particular time or occasion; as, the hour of greatest peril; the man for the hour. "Woman, . . . Mine hour is not yet come." (John II. 4) "This is your hour, and the power of darkness." (Luke xxii. 53) 4. A measure of distance traveled. "Vilvoorden, three hours from Brussels." (J. P. Peters) After hours, after the time appointed for one's regular labour. Canonical hours. See Canonical. 5. <astronomy> Hour angle, a line on which the shadow falls at a given hour; the intersection of an hour circle which the face of the dial. Hour plate, the plate of a timepiece on which the hours are marked; the dial. Sidereal hour, the twenty-fourth part of a sidereal day. Solar hour, the twenty-fourth part of a solar day. The small hours, the early hours of the morning, as one o'clock, two o'clock, etc. To keep good hours, to be regular in going to bed early. Origin: OE. Hour, our, hore, ure, OF. Hore, ore, ure, F. Heure, L. Hora, fr. Gr, orig, a definite space of time, fixed by natural laws; hence, a season, the time of the day, an hour. See Year, and cf. Horologe, Horoscope. Source: Websters Dictionary (01 Mar 1998) |
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| hourglass contraction | Constriction of the middle portion of a hollow organ, such as the stomach or the gravid uterus. (05 Mar 2000) |
| hourglass head | In congenital syphilis, a skull with depressed coronal suture. (05 Mar 2000) |
| hourglass murmur | One in which there are two areas of maximum loudness decreasing to a point midway between the two. (05 Mar 2000) |
| hourglass pattern | A vigorous ringlike contraction observed angiographically in the left ventricular angiogram in the right anterior oblique projection, resembling an hourglass; it is seen in the prolapsed mitral valve leaflet syndrome. (05 Mar 2000) |
| hourglass stomach | A condition in which there is a central constriction of the wall of the stomach dividing it into two cavities, cardiac and pyloric. Synonym: bilocular stomach, ectasia ventriculi paradoxa. Leather-bottle stomach, marked thickening and rigidity of the stomach wall, with reduced capacity of the lumen although often without obstruction; nearly always due to scirrhous carcinoma, as in linitis plastica. Synonym: sclerotic stomach. (05 Mar 2000) |
| hourglass vertebrae | The radiographic appearance of some vertebrae in osteogenesis imperfecta tarda. (05 Mar 2000) |
| milligram hour | An obsolete term for a unit of exposure in radium therapy, i.e., the application of 1 milligram of radium during 1 hour. Synonym: milligramage. (05 Mar 2000) |
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| kilowatt-hour | <unit> A standard measure of electrical energy, equals one kilowatt of power delivered for one hour. Equivalent to 3.6 million joules. For example, 1 kWh will light a 100-watt light bulb for 10 hours. 1 kWh = 3,413 Btu. Abbreviation: kWh (05 Dec 1998) |
| 24-hour cardiac monitor | <apparatus> A recording device, worn by the patient for the purpose of monitoring the hearts rhythm and rate, over a period of 24 hours. (27 Sep 1997) |