Dictionary of Music - Birding America

292 organ pointfrom the fifteenth century. Later ones were composedin the sixteenth century by Girolamo Cavazzoni,and in the seventeenth century by Frescobaldi,Claudio Merulo, Andrea Gabrieli, and severalFrench composers, among them Couperin. In mostorgan Masses the singers’ part is plainsong (with onevoice-part), followed by an organ part that elaborateson the plainsong polyphonically (with numerousvoice-parts).organ pointorgan stopsSee PEDAL POINT.See under ORGAN.organum (ôr′gə nəm) pl. organa (ôr′gə nə)Latin. A general name for the oldest form ofpolyphony (music with more than one voice-part).The earliest surviving organum dates from the ninthcentury, when a lower part was added to a plainsongmelody that duplicated the melody, note for note,but either a fourth or a fifth lower. Thus, if themelody sounded the notes A G F, for example, thesecond part would sound either the D E B♭ immediatelybelow, or the E D C. The first is calledorganum at the fifth and the second organum at thefourth. Both are examples of parallel or strictorganum, since the two parts move exactly parallelto one another (both go down by the same intervals).Occasionally, the original and/or the new partwould be doubled, that is, the notes an octavehigher or lower would also be sounded (D–D′,E–E′, B♭–B♭′, so that a total of three or four noteswould sound at one time). During the eleventh centurya new feature appeared. Occasionally the newpart would move not parallel to the original part, butin the opposite direction, that is, down in pitchwhen the original moved up, or up when it moveddown, in contrary motion. As a result, the two partssometimes crossed, and the original no longer wasalways the higher part. Out of this grew anotherpractice, that of adding a second part above theoriginal instead of below it. However, the onlyintervals still used in adding parts were the perfectintervals, the fourth, fifth, and octave (see INTER-VAL, def. 2). By the middle of the twelfth century,the two parts were no longer note against note.Instead, the added part might have many notes foreach note of the original, which must have beensung quite slowly. As a result, the original part, withits fixed melody (cantus firmus) in long-held notes,came to be called the tenor (from the Latin tenere,meaning “to hold”) and the added part was calledorganum. The older style, with both parts having anequal number of notes, was called DISCANTUS (def.2). The school of St. Martial and the first great composerof the succeeding school of Notre Dame,Leonin, used both the old and the new styles oforganum, often in the same composition. Leoninusually alternated the two. His works are still in twovoice-parts, called organum duplum (the secondpart being called duplum). His successor, Perotin,often used three voice-parts (organum triplum),and, in at least two cases, four parts (organumquadruplum). When, still later, texts were added tothe melismatic upper parts, it created a very importantform of vocal polyphony, the MOTET. Ourknowledge of organum comes largely from theMagnus liber organi de graduali et antifonario(“Great Book of Organum for Graduals andAntiphons”) of c. 1170, the principal collection oftwo-voice polyphony from this period. Thought tohave been written by Leonin and revised by Perotin,it survives in three slightly different versions.Orgel (ôr′gəl).orgue (ôrg).The German word for ORGAN.The French word for ORGAN.orgue de barbarie (ôrg d ə bAr bA rē′).French term for BARREL ORGAN.orgue expressif (ôrg ex pre sēf′).term for HARMONIUM.TheThe Frenchornaments Also, embellishments; British, graces.A general term for extra notes or groups of noteswith which composers and/or performers adorn amelody. Depending on their nature, they mayenliven the melody or the rhythm, or enrich the harmony.The use of ornaments has varied widely fromperiod to period. Sometimes the exact notes to beused are written out, but in earlier periods they werefrequently left up to the performer. In the sixteenthcentury signs began to be used as abbreviations for