| bottom | 1. The lowest part of anything; the foot; as, the bottom of a tree or well; the bottom of a hill, a lane, or a page. "Or dive into the bottom of the deep." (Shak) 2. The part of anything which is beneath the contents and supports them, as the part of a chair on which a person sits, the circular base or lower head of a cask or tub, or the plank floor of a ship's hold; the under surface. "Barrels with the bottom knocked out." (Macaulay) "No two chairs were alike; such high backs and low backs and leather bottoms and worsted bottoms." (W. Irving) 3. That upon which anything rests or is founded, in a literal or a figurative sense; foundation; groundwork. 4. The bed of a body of water, as of a river, lake, sea. 5. The fundament; the buttocks. 6. An abyss. 7. Low land formed by alluvial deposits along a river; low-lying ground; a dale; a valley. "The bottoms and the high grounds." 8. The part of a ship which is ordinarily under water; hence, the vessel itself; a ship. "My ventures are not in one bottom trusted." (Shak) "Not to sell the teas, but to return them to London in the same bottoms in which they were shipped." (Bancroft) Full bottom, a hull of such shape as permits carrying a large amount of merchandise. 9. Power of endurance; as, a horse of a good bottom. 10. Dregs or grounds; lees; sediment. at bottom, At the bottom, at the foundation or basis; in reality. "He was at the bottom a good man." To be at the bottom of, to be the cause or originator of; to be the source of. "He was at the bottom of many excellent counsels." (Addison) To go to the bottom, to sink; especially. To be wrecked. To touch bottom, to reach the lowest point; to find something on which to rest. Origin: OE. Botum, botme, AS. Botm; akin to OS. Bodom, D. Bodem, OHG. Podam, G. Boden, Icel. Botn, Sw. Botten, Dan. Bund (for budn), L. Fundus (for fudnus), Gr. (for), Skr. Budhna (for bhudhna), and Ir. Bonn sole of the foot, W. Bon stem, base. 257>. Cf. 4th Found, Fund. Source: Websters Dictionary (01 Mar 1998) |
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| bottom ash | Noncombustable ash that is left after solid fuel has been burned. (05 Dec 1998) |
| sulphur-bottom | <zoology> A very large whalebone whale of the genus Sibbaldius, having a yellowish belly; especially, S. Sulfureus of the North Pacific, and S. Borealis of the North Atlantic. Synonym: sulphur whale. Source: Websters Dictionary (01 Mar 1998) |
| live bottom | A material storage bin or truck with a floor which incorporates a device for removing or unloading the material contained in the bin. (05 Dec 1998) |
| atrial echo | Electrical reactivation of the atrium by a retrograde impulse returning from the A-V node while the antegrade impulse continues to the ventricle; characterised electrocardiographically, by a pair of P waves enclosing a QRS complex, the second P wave being inverted, indicating that it is the reverse (the retrograde pathway) of the pathway of the first P wave (the antegrade pathway). (05 Mar 2000) |
| spin echo | A commonly used technique to recover T2 relaxation signals in magnetic resonance imaging, by using a 180 |
| nodus sinuatrialis echo | A postectopic sinus beat occurring earlier than would be expected from the preceding sinus node discharge interval; i.e., the interval following a premature beat of supraventricular origin is less than the ordinary cycle length between sinus beats, whereas ordinarily the interval would be expected to exceed cycle length. (05 Mar 2000) |
| echo | Origin: L. Echo, Gr. Echo, sound, akin to, sound, noise; cf. Skr. Va to sound, bellow; perh. Akin to E. Voice: cf. F. Echo. 1. A sound reflected from an opposing surface and repeated to the ear of a listener; repercussion of sound; repetition of a sound. "The babbling echo mocks the hounds." (Shak) "The woods shall answer, and the echo ring." (Pope) 2. Sympathetic recognition; response; answer. "Fame is the echo of actions, resounding them." (Fuller) "Many kind, and sincere speeches found an echo in his heart." (R. L. Stevenson) 3. A wood or mountain nymph, regarded as repeating, and causing the reverberation of them. "Sweet Echo, sweetest nymph, that liv'st unseen Within thy airy shell." (Milton) A nymph, the daughter of Air and Earth, who, for love of Narcissus, pined away until nothing was left of her but her voice. "Compelled me to awake the courteous Echo To give me answer from her mossy couch." (Milton) Echo organ, a stop upon a harpsichord contrived for producing the soft effect of distant sound. To applaud to the echo, to give loud and continuous applause. "I would applaud thee to the very echo, That should applaud again." (Shak) Source: Websters Dictionary (01 Mar 1998) |
| echo beat | Extrasystole produced by the return of an impulse in the heart retrograde to a focus near its origin which then returns antegradely to produce a second depolorization. (05 Mar 2000) |
| echo-free | The property of appearing echo-free or without echoes on a sonographic image; a clear cyst appears anechoic. See: transonic. Synonym: echo-free. Origin: G. An-priv. + echo + ic (05 Mar 2000) |
| echo planar | A method of magnetic resonance imaging that allows rapid image acquisition during free induction decay, using technically difficult rapidly oscillating radiofrequency gradients. (05 Mar 2000) |
| echo-planar imaging | A type of magnetic resonance imaging that uses only one nuclear spin excitation per image and therefore can obtain images in a fraction of a second rather than the minutes required in traditional mri techniques. It is used in a variety of medical and scientific applications. (12 Dec 1998) |
| echo reaction | A disorder of speech where there is an involuntary repetition several times of the same word. (27 Sep 1997) |
| echo speech | A disorder of speech where there is an involuntary repetition several times of the same word. (27 Sep 1997) |