1. Mus. The first, i.e., lowest, note of the scale of any key, which forms the basis of, and gives its name to, the key; the tonic. (Formerly called simply key: see KEY sb.1 7 a.) In quot. 1776 applied to the lowest tone of an ancient Greek scale or ‘mode.’
1776. Burney, Hist. Mus., I. v. 460. The key-note of the Dorian mode. Ibid. (1782), II. ii. 97. Transposed keys … represented by other sounds in the same relation to the key-note.
1859. Jephson, Brittany, iv. 41. They never leave off on the key-note; the ear is left unsatisfied.
1875. Ouseley, Mus. Form, ii. 11. A melodic perfect cadence must end with the key-note.
b. transf. = KEY sb.1 8 a. rare.
1762. Kames, Elem. Crit., XVIII. iv. (1774), II. 104. In reading, whether verse or prose, a certain tone is assumed, which may be called the key-note; and in that tone the bulk of the words are sounded.
2. fig. The leading idea of a discourse, composition, or course of action; the prevailing tone of thought or feeling.
1783. Blair, Rhet., II. xxxi. 166. Much of the Orator’s art and ability is shown, in thus striking properly at the commencement, the key note, if we may so express it, of the rest of his Oration.
1825. Scott, Diary, 22 Dec., in Lockhart. I wrote a few verses … taking the key-note from the story of Clavers leaving the Scottish Convention of estates in 1688–9.
1862. ‘Shirley’ (J. Skelton), Nugæ Crit., ix. 404. This moderation was the key-note of Canning’s character, and determined his political career.
1875. Stubbs, Const. Hist., III. xviii. 14. The keynote of the Lancastrian policy.
1888. Burgon, Lives 12 Gd. Men, I. ii. 140. Such was the frequent keynote of his discourses in public.
