Dictionary of Music - Birding America

196 intonationIn other systems of temperament, however, such asthat of Pythagoras or that of JUST INTONATION, thehalf tones of the chromatic scale are not equal, andthe distance between C and C-sharp, for example,differs from that between C-sharp and D. A majorthird, which is made up of four half tones, measures400 cents in equal temperament, 408 cents in thePythagorean system of tuning, and 386 cents in justintonation.intonation 1 A performer’s accuracy with respectto pitch. Good intonation means playing or singingnotes exactly on pitch; poor intonation means thatthe notes produced are above (sharp) or below (flat)their proper pitches. 2 In Gregorian chant, the openingnotes of a PSALM TONE. 3 See JUST INTONATION.intrada (ēn trä′dä) Italian: “entrance.” 1 In thesixteenth and seventeenth centuries, an instrumentalpiece or section used to announce an entrance, opena festivity, or begin a suite. 2 A name occasionallyused by Mozart, Beethoven, and others for a shortoverture.introduction A short opening section of a longercomposition, especially a slow section preceding thefirst (fast) movement of a concerto, symphony, orstring quartet.Introit (in′trō it, in′troit). In the Roman Catholicrites, the first musical section of the Proper of theMass (see MASS).invention A title used by several composers ofthe baroque period (1600–1750) for instrumentalpieces of various kinds. The most famous are fifteenkeyboard pieces by Bach, which he entitledInvenziones and which today are usually called hisTwo-Part Inventions since they are written in twopartcounterpoint. (Another collection of thembears the name Praeambulum.) A similar group offifteen pieces, which Bach called Sinfonie (it is notknown why, since sinfonia meant a quite differentform in Bach’s day, and in another collection calledFantasia), is known as his Three-Part Inventions;they resemble the first group in style but have threevoice-parts.inversion 1 The procedure or result of shifting anote of an interval or chord so that what was originallythe bass (the lowest note) becomes an uppernote. An interval (a group of two notes sounded atthe same time) is inverted by moving its lower noteup one octave, or its higher note down one octave.(See the accompanying example A, in which D–A,which is a fifth, has been turned, by either of the twopossible inversions, into a fourth.) Similarly, a secondwould be changed into a seventh, a third into asixth, a fourth into a fifth. (Note that the sum of thetwo intervals is always nine, and that the intervalstogether form an octave.) Although the perfect intervals(fourth, fifth, octave) remain perfect despiteinversion, an inverted major interval becomes aminor interval (and vice versa), whereas an augmentedinterval becomes a diminished interval (andvice versa). (See INTERVAL, def. 2, for an explanationof these terms.)fig. 135 p/u from p. 201A chord is inverted when its root (lowest note) ismoved up an octave. If only the root is moved, thechord is said to be in first inversion. The triadC–E–G, for example, would become E–G–C. A triadin first inversion is sometimes called a six-threechord or a sixth chord, because its upper notes area sixth and a third above the bass. If the note justabove the root is also moved up an octave, the chordis said to be in second inversion. The chord C–E–G,for example, would then become G–C–E. A triad insecond inversion is sometimes called a six-fourchord, because its upper notes are a sixth and afourth above the bass. (See also CHORD.) A triad,which consists of three notes, has only two possibleinversions. A seventh chord, consisting of fournotes, has three inversions. The first inversion ofC–E–G–B♭, for example, is E–G–B♭–C, which issometimes called a six-five chord because its uppermostnotes are a sixth and a fifth above the bass. Thesecond inversion, G–B♭–C–E, is sometimes called afour-three chord; and the third inversion,B♭–C–E–G, is sometimes called a four-two chord.The theory of inversion, according to which chords