ˈactivate, v.
[f. active a. + -ate3. Cf. captiv-ate, and mod.Fr. activer.]
a. To make active, move to activity. Cf. actuate. Hence ˈactivated ppl. a., ˈactivating ppl. a. and vbl. n.
| 1626 Bacon Sylva §83 For as Snow and Ice especially, being holpen and their cold Activated by nitre or salt, will turn water into Ice and that in a few hours. 1642 Bp. R. Montagu Acts & Mon. 190, I cannot see that he would consent with Ambrose, that they [the Sibyls] were activated by the Deuill. 1673 O. Walker Education (1677) 124 This warms and activates the spirit in the search of truth. 1858 Bennet Nutrition ii. 42 Increased muscular vigour..activates respiration. 1905 Sat. Westm. Gaz. 15 July 13 The young English dramatist has very few opportunities of making the hair of the Philistine stand on end or activating his digestion. 1926 J. A. Thomson Man in Light of Evol. 10 The rarely activated muscles of our ear-trumpet. 1926 Public Opinion 22 Oct. 408/3 The planet and its activating sun. 1940 H. G. Wells Babes in Darkling Wood ii. iii. 195 She wanted ‘activating’. She had recently acquired that word. 1961 Essays & Stud. XIV. 76 The motives of self-appointed moralists... Are they activated by concern for public morality? 1962 Amer. Speech XXXVII. 271 A flat plate set in the pavement to detect traffic in order to activate traffic lights. |
b. spec.: (a) Chem., to render active, reactive, excited (of carbon, molecules, etc.); activated carbon, carbon, esp. charcoal, which has been treated to increase its adsorptive power; (b) Physics, to make radioactive; (c) to aerate (sewage) as a means of purification; activated sludge, aerated sewage containing aerobic bacteria.
| 1902 Jrnl. Soc. Chem. Industry XXI. 1102/2 Schönbein..found that sulphurous acid had a remarkable ‘activating’ (activirende) effect on various oxidising substances, i.e., they were considerably more active in the presence of small quantities of sulphurous acid. 1903 Electr. World & Engineer 10 Jan. 86 (C.D. Suppl.), Underground air is not like activated air. 1903 Sci. Amer. Suppl. 18 Apr. 22815/1 In these measurements it is necessary to maintain the body to be ‘activated’ for several hours at a negative potential of several thousand volts. 1907 Med. Record 3 Aug. 171 The former [ferment, viz. enterokinase] activates the pancreatic juice. 1919 Jrnl. Industr. & Engin. Chem. XI. 282 The development of activated charcoal as a canister filler was largely the work of two Cleveland organizations. 1921 Glasgow Herald 13 Aug. 5 The new process of producing activated sludge by which complete purification of the sewage is achieved. 1921 Jrnl. Soc. Chem. Industry XL. (Trans.) 230/2 (title) Activated Carbon. 1934 Jrnl. Inst. Sanit. Engin. Sept. 252 The sewage is settled, treated by the activated sludge process, by sand filters and by chlorination. 1937 A. M. Prentiss Chemicals in War xix. 549 The filter [in a gas-mask canister] consists of an oval-shaped perforated sheet-metal container filled with a mixture of 80 per cent activated charcoal and 20 per cent soda lime. 1938 R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity (ed. 2) xi. 133 We find that the wire now shows no initial α-activity after its removal from the activating vessel. Ibid. x. 119 Most of the elements situated between boron and calcium have been activated under the influence of α-rays. 1956 A. H. Compton Atomic Quest 71 Pulling the last activated slugs from the Hanford piles. |
Hence activation (æktɪˈveɪʃən), the action of activating; the state of being activated; in specific uses corresp. to those of the vb.; activation analysis = radioactivation analysis.
Also ˈactivator, one who (rare) or a thing which activates (in various technical senses); a catalyst.
| 1906 Practitioner Dec. 747 Mixed sera from several animals might be used, in the hope of finding one suitable for activation with human serum. 1919 Science L. 568/1 (title) Charcoal activation. 1927 Haldane & Huxley Animal Biol. ii. 54 Activation, or the starting-off of the egg on development. 1930 Engineering 21 Feb. 257/3 At least one of the molecules concerned must be ‘activated’ and this ‘activation’ may well be due to the absorption of radiation. 1931 J. W. McBain Sorption of Gases by Solids iv. 59 Methods of activation always involve heating to more or less elevated temperatures which may range from 350° C to 1,150° C. 1940 Ann. Reg. 1939 371 Gene mutations were generally regarded as due to individual atomic activations. 1949 Atomics Nov. 106/2 Tracers are only rarely radioactive. To overcome this difficulty, the sample may be irradiated either with high energy charged particles or thermal neutrons... This method is known as activation analysis. 1960 Nature CLXXXV. 196 Neutron activation analysis of ancient Roman potsherds. |
| 1911 R. C. Punnett Mendelism (ed. 3) 45 A ferment which behaves as an activator of the chromogen. 1913 Dorland Med. Dict. (ed. 7) 36/1 Activator, a substance which renders some other substance active: especially an inorganic substance which combines with an inactive enzyme to render it capable of effecting its proper reaction. 1948 Electronic Engin. XX. 225 The inclusion of activators such as zinc, copper, antimony..in calcium oxide caused speedy and violent ion-burning. 1958 Spectator 4 July 9/3 They chose Maurice Buckmaster, who later became famous as an activator of the French Resistance. 1962 Lancet 27 Jan. 192/1 The defect in fibrinolytic activity is associated with ‘unavailability’ rather than with an absolute deficiency of tissue activator. 1963 B. Fozard Instrumentation Nucl. Reactors vi. 63 In scintillation phosphors these impurities are known as activators. |