From the second edition (1989):
(ˈkɒnʃəsnɪs) [f. as prec. + -ness.]

1. Joint or mutual knowledge. Obs. rare.

1681 Whole Duty Nations 49 Consciousness, or mutual knowledg of persons and their worship.

2. (Also in early use, consciousness to oneself.) Internal knowledge or conviction; knowledge as to which one has the testimony within oneself; esp. of one's own innocence, guilt, deficiencies, etc. Cf. conscious 3.

1632 Massinger Maid of Hon. i. ii, The consciousness of mine own wants. 16‥ Locke (J.), Had not their consciousness to themselves of their ignorance‥kept them from so idle an attempt. a1744 Pope (J.), An honest mind is not in the power of a dishonest: to break its peace, there must be some guilt or consciousness. 1770 Junius Lett. xxxix. 198 There is‥a palpable consciousness of guilt. 1860 Macaulay Biog. (1867) 11 Bentley‥was supported by the consciousness of an immeasurable superiority. 1875 Jowett Plato (ed. 2) III. 7 Happy in the consciousness of a well-spent life.

3. The state or fact of being mentally conscious or aware of anything. Cf. conscious 6.

1746–7 Hervey Medit. (1818) 215 Let it‥become one with the very consciousness of my existence! 1776 Adam Smith W.N. i. xi. (1869) I. 164 The anxiety of the proprietors‥seems‥to indicate a consciousness‥that this species of cultivation is‥more profitable than any other. 1863 F. A. Kemble Resid. in Georgia 9 It is only to the consciousness of these evils that knowledge and reflection awaken him. 1864 Lewes Hist. Philos. II. 142 The consciousness of my existence is to me the assurance of my existence. 1883 G. Lloyd Ebb & Flow II. 18 For a few moments he lost the consciousness of why he was miserable.

4. a. Philos. The state or faculty of being conscious, as a condition and concomitant of all thought, feeling, and volition; ‘the recognition by the thinking subject of its own acts or affections’ (Hamilton).

1678 Cudworth Intell. Syst. (1837) I. 93 Neither can life and cogitation, sense and consciousness‥ever result from magnitudes, figures, sites, and motions. 1690 Locke Hum. Und. ii. i. §19 Consciousness is the perception of what passes in a Man's own mind. 1707 S. Clarke 2nd Defense (1715) 5 Consciousness, in the most strict and exact Sense of the Word, signifies‥the Reflex Act by which I know that I think, and that my Thoughts and Actions are my own and not Anothers. 1785 Reid Int. Powers i. i, Consciousness is a word used by Philosophers, to signify that immediate knowledge which we have of our present thoughts and purposes, and, in general, of all the present operations of our minds. 1842 Sir W. Hamilton in Reid's Wks. Note B (1872) 810/1 Consciousness is a knowledge solely of what is now and here present to the mind. It is therefore only intuitive, and its objects exclusively presentative. Ibid. 929. 1866 Huxley Phys. viii. 210 We class sensations along with emotions, and volitions, and thoughts, under the common head of states of consciousness. But what consciousness is, we know not; and how it is that anything so remarkable as a state of consciousness comes about as the result of irritating nervous tissue, is just as unaccountable as the appearance of the Djin when Aladdin rubbed his lamp, or as any other ultimate fact of nature. 1875 Bain Emotions & Will (ed. 3) 539.

b. (with a and pl.) State of consciousness.

1805 Wordsw. Prelude iii. 126 From strict analogies by thought supplied Or consciousnesses not to be subdued. 1812 J. C. Hobhouse Journey (1813) 627 A female‥quite dumb, nearly deaf, and possessed of no one consciousness belonging to humanity. a1853 Robertson Serm. Ser. iii. iv. 53 His [man's] will is not his affections, neither are his affections his thoughts‥They are separate consciousnesses, living consciousnesses. 1870 Huxley Lay Serm. (1871) 327 Whatever our marble may be in itself, all that we can know of it is under the shape of a bundle of our own consciousnesses.

5. a. The totality of the impressions, thoughts, and feelings, which make up a person's conscious being. In pl. = Conscious personalities.

1690 Locke Hum. Und. ii. xxvii. (1695) 183 If the same consciousness can be transferr'd from one thinking Substance to another, it will be possible that two thinking Substances may make but one Person. 1708 Brit. Apollo No. 20. 2/1 Those many Consciousnesses must be as the Constituent Parts of that one Individual Consciousness. 1805 Wordsw. Prelude ii. 32 Musing on them, often do I seem Two consciousnesses, conscious of myself, And of some other Being. 1877 E. R. Conder Bas. Faith ii. 91 From our innermost consciousness, a voice is heard, clothed with native authority‥‘I feel. I think. I will. I am.’

b. Limited by a qualifying epithet to a special field, as the moral consciousness or religious consciousness.

1863 M. Howitt F. Bremer's Greece II. xvi. 157 The commencement of a moral consciousness. 1884 H. Spencer in 19th Cent. XV. 1 Unlike the ordinary consciousness, the religious consciousness is concerned with that which lies beyond the sphere of sense.

c. Attributed as a collective faculty to an aggregate of men, a people, etc., so far as they think or feel in common.

1837 H. Martineau Soc. Amer. III. 198 While few can be found to agree even upon matters of so-called universal consciousness. a1871 Grote Plato Pref. (1875) 7 Such intellects broke loose from the common consciousness of the world around them. 1876 E. White Life in Christ i. viii. 88 The religious consciousness of the age.

6. The state of being conscious, regarded as the normal condition of healthy waking life.

1837 Dickens Pickw. xxi, When the fever left him, and consciousness returned, he awoke to find himself rich and free. 1868 Bain Ment. & Mor. Sc. App. 93 In one class of [popular] applications, consciousness is mental life, as opposed to torpor or insensibility; the loss of consciousness is mental extinction for the time. 1885 W. L. Davidson Logic of Defin. 136 The mind's wakeful activity is consciousness—consciousness as opposed to dormancy, dreamless sleep, swoon, insensibility.

7. double consciousness: see quot.

1882 Syd. Soc. Lex., Double consciousness, a condition which has been described as a double personality, showing in some measure two separate and independent trains of thought and two independent mental capabilities in the same individual.

8. Comb., as consciousness-expanding a. = psychedelic a.; consciousness-raising orig. U.S., the activity or experience of increasing (esp. social, political, etc.) sensitivity or awareness: see raise v. 19d; freq. attrib.; hence consciousness-raiser, one who or that which raises consciousness.

1967 Psychic News 26 Aug. 7/4 Mescalin, LSD and the like have an awakening, *consciousness-expanding effect. 1968 J. Drummond Gantry Episode iii. 34 They talk about a psychedelic drug, a ‘consciousness-expanding’ drug. 1974 National Rev. (U.S.) 12 Apr. 428/2 Left-nationalist *consciousness-raisers succeeded in persuading only 5 per cent of voters to worry about American economic domination. 1976 Miller & Swift Words & Women (1977) viii. 135 Varda One, editor of Everywoman, says that words like manglish‥and herstory are ‘reality-violators and consciousness-raisers’. 1983 Times 14 Feb. 8/7 Lesbians, anti-enfibulators, peace protesters and consciousness-raisers. 1968 Notes from First Year June 15 If there is anything we can learn from the black liberation movement, it is that the primary job is *consciousness-raising. 1969 Women, Jrnl. of Liberation Fall 55/1 Women's Day—the first of what promises to be many positive, consciousness-raising occasions. 1979 Time 2 Apr. 13/3 For them the anti-Shah revolution‥proved an experience that, in the West, would be called consciousness raising. 1985 Amer. Speech LX. 13 Terms such as consciousness-raising, sex object,‥and Ms., through which women have attempted to replace the received patriarchal names with a new vernacular articulating their own‥perceptions.