| time | 1. Duration, considered independently of any system of measurement or any employment of terms which designate limited portions thereof. "The time wasteth [i. E. Passes away] night and day." (Chaucer) "I know of no ideas . . . That have a better claim to be accounted simple and original than those of space and time." (Reid) 2. A particular period or part of duration, whether past, present, or future; a point or portion of duration; as, the time was, or has been; the time is, or will be. "God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets." (Heb. I. 1) 3. The period at which any definite event occurred, or person lived; age; period; era; as, the Spanish Armada was destroyed in the time of Queen Elizabeth; often in the plural; as, ancient times; modern times. 4. The duration of one's life; the hours and days which a person has at his disposal. "Believe me, your time is not your own; it belongs to God, to religion, to mankind." (Buckminster) 5. A proper time; a season; an opportunity. "There is . . . A time to every purpose." (Eccl. Iii. 1) "The time of figs was not yet." (Mark xi. 13) 6. Hour of travail, delivery, or parturition. "She was within one month of her time." (Clarendon) 7. Performance or occurrence of an action or event, considered with reference to repetition; addition of a number to itself; repetition; as, to double cloth four times; four times four, or sixteen. "Summers three times eight save one." (Milton) 8. The present life; existence in this world as contrasted with immortal life; definite, as contrasted with infinite, duration. "Till time and sin together cease." (Keble) 9. Tense. 10. The measured duration of sounds; measure; tempo; rate of movement; rhythmical division; as, common or triple time; the musician keeps good time. "Some few lines set unto a solemn time." (Beau. & Fl) Time is often used in the formation of compounds, mostly self-explaining; as, time-battered, time-beguiling, time-consecrated, time-consuming, time-enduring, time-killing, time-sanctioned, time-scorner, time-wasting, time-worn, etc. Absolute time, time irrespective of local standards or epochs; as, all spectators see a lunar eclipse at the same instant of absolute time. Apparent time, the time of day reckoned by the sun, or so that 12 o'clock at the place is the instant of the transit of the sun's center over the meridian. Astronomical time, mean solar time reckoned by counting the hours continuously up to twenty-four from one noon to the next. At times, at distinct intervals of duration; now and then; as, at times he reads, at other times he rides. Civil time, time as reckoned for the purposes of common life in distinct periods, as years, months, days, hours, etc, the latter, among most modern nations, being divided into two series of twelve each, and reckoned, the first series from midnight to noon, the second, from noon to midnight. Common time Apparent time as reckoned from the transit of the sun's center over the meridian. 1. To appoint the time for; to bring, begin, or perform at the proper season or time; as, he timed his appearance rightly. "There is no greater wisdom than well to time the beginnings and onsets of things." (Bacon) 2. To regulate as to time; to accompany, or agree with, in time of movement. "Who overlooked the oars, and timed the stroke." (Addison) "He was a thing of blood, whose every motion Was timed with dying cries." (Shak) 3. To ascertain or record the time, duration, or rate of; as, to time the speed of horses, or hours for workmen. 4. To measure, as in music or harmony. Origin: OE. Time, AS. Tima, akin to tid time, and to Icel. Timi, Dan. Time an hour, Sw. Timme. 58. See Tide. (01 May 1998) |
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| time and motion studies | The observation and analysis of movements in a task with an emphasis on the amount of time required to perform the task. (12 Dec 1998) |
| time compensation gain | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| time constant | That part of a circuit that determines the time interval over which the rate of electrical events will be averaged; in pulmonary physiology, the factors determining rate of flow in the airways. (05 Mar 2000) |
| time factors | Elements of limited time intervals, contributing to particular results or situations. (12 Dec 1998) |
| time lapse | <technique> Technique applied to speed up the action in a film or videotape sequence. In filming by taking a frame every few seconds and projecting at conventional speed (16 or 24 frames per second), the movements of cells can be greatly speeded up and then become conspicuous. With videotape, the recording is made at slow tape speed and replayed at full speed. The opposite of slow motion. (28 May 1998) |
| time management | Planning and control of time to improve efficiency and effectiveness. (12 Dec 1998) |
| time marker | An instrument that marks the time, usually in seconds or fractions of seconds, on a kymograph record in physiologic experiments. (05 Mar 2000) |
| time of flight | The time for a photon created by annihilation of a positron-electron pair to reach a detector; since annihilation photons are created in pairs and travel in opposite directions at about 3 × 1010 cm/sec, measurement of the difference in arrival time at detectors with sub-nanosecond resolution allows calculation of the location of the event; the basic physics of positron emission tomography. (05 Mar 2000) |
| time perception | The ability to estimate periods of time lapsed or duration of time. (12 Dec 1998) |
| time sense | The faculty by which the passage of time is appreciated. (05 Mar 2000) |
| time-compensated gain | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| time-gain compensation | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| time-lapse microscopy | Microscopy in which the same object (e.g., a cell) is photographed at regular time intervals over several hours. (05 Mar 2000) |
| time-varied gain | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| activated clotting time | The most common test used for coagulation time in cardiovascular surgery. (05 Mar 2000) |
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| activated partial thromboplastin time | The time needed for plasma to form a fibrin clot following the addition of calcium and a phospholipid reagent; used to evaluate the intrinsic clotting system. (05 Mar 2000) |
| A-H conduction time | Forward conduction of the cardiac impulse from atria to ventricles via the A-V node or any bypass tract, represented in the electrocardiogram by the P-R interval. P-H conduction time is from the onset of the P wave to the first high frequency component of the His bundle electrogram (normally 119 ± 38 msec); A-H conduction time is from the onset of the first high frequency component of the atrial electrogram to the first high frequency component of the His bundle electrogram (normally 92 ± 38 msec); P-A conduction time is from the onset of the P wave to the onset of the atrial electrogram (normally 27 ± 18 msec). (05 Mar 2000) |
| association time | Time elasping between a stimulus and the verbalised response to it. (05 Mar 2000) |
| biologic time | The concept that our appreciation of time varies with age and is governed by the neural organization of the individual; it obeys a logarithmic rather than an arithmetic law. (05 Mar 2000) |
| bleeding time | <haematology> A test which measures the time it takes for small blood vessels to close off and bleeding to stop. Abnormal results can be seen in those with congenital or acquired platelet function disorders or thrombocytopenia. (27 Sep 1997) |
| blood circulation time | Determination of the shortest time interval between the injection of a substance in the vein and its arrival at some distant site in sufficient concentration to produce a recognizable end result. It represents approximately the inverse of the average velocity of blood flow between two points. (12 Dec 1998) |
| P-A conduction time | See: atrioventricular conduction. (05 Mar 2000) |
| generation time | <cell biology> Time taken for a cell population to double in numbers and thus equivalent to the average length of the cell cycle. (18 Nov 1997) |
| reaction time | The time from the onset of a stimulus until the organism responds. (12 Dec 1998) |
| real-time ultrasonography | Rapid serial ultrasound images produced using a phased array or scanning transducer; produces a video display of organ motion, such as heart valve or foetal motion. (05 Mar 2000) |
| recognition time | The interval between the application of a stimulus and the recognition of its nature. (05 Mar 2000) |
| partial thromboplastin time | Test of the intrinsic (factors viii, ix, xi, and xii) and common (fibrinogen, prothrombin, factors v and x) pathways of coagulation in which a mixture of plasma and phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides) is recalcified and the time required for the appearance of fibrin strands measured. Activation may be provided by contact with the glass tube or exposure to activators (e.g., ellagic acid, particulate silicates such as diatomaceous earth or kaolin) before addition of the calcium chloride. It is used as a screening test and to monitor heparin therapy. (12 Dec 1998) |
| relaxation time | Time taken for a system to return to the resting or ground state or a new equilibrium state following perturbation. Often used in context of receptor systems that have a refractory period after responding and then relax to a competent state. Can be used more precisely to mean the time for a system to change from its original equilibrium value to 1/e of this original value. (18 Nov 1997) |
| median time to elimination | <pharmacology> The time it takes one half of a drug to be eliminated from the body. (09 Oct 1997) |