coherent, a. (and n.)
(kəʊˈhɪərənt)
Also 8 cohær-.
[a. F. cohérent, ad. L. cohærēnt-em, pr. pple. of cohærēre to cohere.]
A. adj.
1. a. That sticks or clings firmly together; esp. united by the force of cohesion. Const. to, with. Said of a substance, material, or mass, as well as of separate parts, atoms, etc.
| 1578 Banister Hist. Man i. 29 The thyrd [bone of the wrest], is with the second coherent. 1626 Bacon Sylva §298 Most Powders grow more close and coherent by mixture of Water, than by mixture of Oyl. 1709 Blair in Phil. Trans. XXVII. 85 The Fasciculi were more strictly coherent to one another. 1869 Roscoe Elem. Chem. 221 The metal barium has not yet been obtained in the coherent state. 1878 Huxley Physiogr. 21 These rocks are sufficiently coherent to form durable building stones. |
b. spec. in Bot.: United by cohesion, q.v.
| 1830 Lindley Nat. Syst. Bot. 171 Seed without its proper integuments, its testa being coherent with the utricle. 1872 Oliver Elem. Bot. i. iv. 37 Primrose: the sepals coherent. |
† c. coherent small-pox (see quot.). Obs.
| 1722 Jurin Small Pox in Phil. Trans. XXXII. 191 Small Pox, of that sort which is call'd the cohærent, or the middle between the distinct and the confluent kind. |
d. Various spec. senses in Physics (see quots.).
| 1902 Mann & Millikan tr. Drude's Theory of Optics 134 If two sources are to produce interference, their phases must always be either exactly the same or else have a constant difference. Such sources are called coherent. 1937 Frank & Tamm in Compt. Rend. Acad. Sci. URSS XIV. 109 (heading) Coherent visible radiation of fast electrons passing through matter. 1938 Physical Rev. LIV. 500/2 The theory [of Frank and Tamm] implies that the radiation emitted by the electron along its path is coherent. 1939 I. Tamm in Jrnl. Physics USSR I. 454 The experimental investigation of the Cerenkov radiation is made possible..by the fact that in the visible region the intensity of the coherent radiation is much greater than that of the Bremsstrahlung. 1957 Gloss. Terms Nucl. Sci. (Nat. Res. Council, U.S.) 151/2 Scattering of particles or photons in which there are definite phase relationships between the incoming and the scattered waves, is termed coherent scattering. 1958 Chambers's Techn. Dict. 967/2 Coherent oscillator, one which is stabilised by being locked to the transmitter of a radar set for beating with a reflected incoming pulse signal. 1960 Cooke & Markus Electronics & Nucleonics Dict., Coherent radiation, radiation in which there are definite phase relationships between different points in a cross-section of the beam... Interference bands are observed only between coherent beams. 1961 Ann. Reg. 1960 xi. 396 This light was different from that in the flash since the tripping action of the first light to be produced ensured that all subsequent quanta were produced with light waves in synchronism with it. In other words, the light produced from the laser was ‘coherent’. 1963 Standard News Mar. 58/1 The action of a laser is to emit light of very narrow bandwidth and considerable intensity—what is called coherent light. 1965 New Scientist 16 Sept. 676/2 A far simpler data-processing system results from the use of coherent light. |
2. transf. of non-material cohesion.
| 1655–60 Stanley Hist. Philos. (1701) 184/2 If there are intelligibles, and those neither sensibles, nor coherent with sensibles. 1660 Boyle Seraphic Love 104 Controversies..about Prædestination, and the coherent doctrines. a 1677 Barrow Serm. Wks. 1716 I. 225 Coherent with this is a Third property of..love. a 1718 Penn Tracts Wks. 1726 I. 594 Most times Points are to be prov'd by comparing and weighing Places coherent. 1855 H. Spencer Princ. Psychol. (1872) I. ii. ii. 178 Among the successive auditory feelings there are definite and coherent combinations of groups. 1876 J. H. Newman Hist. Sk. I. i. iii. 149 An empire, more stable, more coherent than any Turkish rule before it. |
† 3. Accordant or related logically or in sense; congruent; harmoniously accordant. Obs.
| c 1555 Harpsfield Divorce Hen. VIII (1878) 39 These places are nothing coherent to the state of our present question. 1593 Bilson Govt. Christ's Ch. 100 As most coherent with the Text. 1601 Shakes. All's Well iii. vii. 39 That time and place with this deceite so lawfull May proue coherent. |
4. a. Of thought, speech, reasoning, etc.: Of which all the parts are consistent, and hang well together.
| 1580 North Plutarch (1676) 991 A Speech not coherent and hanging well together. 1678 Cudworth Intell. Syst. 879 Good Coherent Sense. a 1714 Burnet Own Time (1766) I. 438 The story is so coherent. 1869 Freeman Norm. Conq. (1876) III. xii. 230 The Norman accounts are anything but satisfactory or coherent. |
b. said of persons.
| 1724 Watts Logic iii. iv. §1 A coherent thinker, and a strict reasoner, is not to be made at once by a set of rules. 1848 Dickens Dombey 51 Be plain and coherent, if you please. |
† B. n. a. One who coheres or combines with others. b. That which coheres or is connected. (In quot. 1657, ‘context’; = coherence 5.) Obs.
| 1598 Florio, Complice, a partaker, a complice, a confederate, a coherent. 1617 Markham Caval. viii. 17 A world of such deceits, which doe depend and are coherents to his former mischiefes. 1657 Burton's Diary (1828) II. 306 [He] moved, that the coherents might be read, to explain it. |