tetrachord
(ˈtɛtrəkɔːd)
[ad. Gr. τετράχορδον (sc. ὄργανον), a Greek musical instrument, f. τετρα- tetra- + χορδή string.]
1. An ancient musical instrument with four strings.
| 1603 Holland Plutarch Explan. Words, Tetrachord, an instrument in old time of foure strings. 1814 Mann. & Cust. in Ann. Reg. 490/1 Most of the Greek women sing in a pleasing manner, accompanying themselves with a tetrachord, the tones of which are an excellent support to the voice. 1849 Donaldson Theat. Greeks (ed. 6) i. ii. 15 Terpander..substituted the seven-stringed cithara for the old tetrachord. |
2. Mus. A scale-series of four notes, being the half of an octave. † b. The interval between the first and last notes of this series; a perfect fourth.
| 1603 Holland Plutarch's Mor. 1254 It was not for ignorance that in the Dorian tunes they forbare this Tetrachord. 1694 W. Holder Harmony iv. (1731) 66 (Table of Intervals), 4th, Diatessaron, Tetrachord. 1704 J. Harris Lex. Techn. I, Tetrachord, in Musick, is a Concord or Interval of 3 Tones. The Tetrachord of the Ancients was a rank of four Strings. 1847 Grote Greece ii. xvi. III. 285 Such were the three modes or scales, each including only a tetrachord, upon which the earliest Greek masters worked. 1890 Athenæum 4 Jan. 24/3 The tetrachord [on an Arab lute] thus comprised c, d, e flat, e, and f. |
c. transf. A stanza of four lines. rare.
| 1817 N. Drake Shakspeare I. 54 The Octant, of two tetrachords of disjunct alternate rhime. Ibid. 55 Three tetrachords in alternate rhime. |
Hence tetraˈchordal a., of or pertaining to a tetrachord or tetrachords. Also ‖ tetrachordon (-ˈkɔːdɒn) [see quot. 1876], an instrument like a cottage pianoforte in form, in which the strings are pressed against a revolving cylinder to produce the tone.
| 1740 J. Grassineau Mus. Dict. 274 Tetrachordon. See Tetrachord. ? 1850 S. A. Glover (title) Manual, containing a development of the tetrachordal System. 1876 Stainer & Barrett Dict. Mus. Terms s.v. Tonic Sol-fa, Miss Sarah A. Glover, of Norwich, about thirty years ago projected and taught..a system which she called the tetrachordal system, which was the Tonic Sol-fa notation in its original form. Ibid., Tetrachordon..[so] called..from an idea that its sounds are similar to those produced by a string quartet. |