1. 
   Pentachord
   Pen'ta·chord noun [ Latin pentachordus five-stringed, Greek ...; ... five + ... string.] 1. An ancient instrument of music with five strings. 2. An order or system of five sounds. Busby.
   Found op http://www.encyclo.co.uk/webster/P/48
   
   
2. 
   Pentachord
   • (n.) An order or system of five sounds. • (n.) An ancient instrument of music with five strings.
   Found op http://thinkexist.com/dictionary/meaning/pentachord/
   
   
3. 
   Pentachord
   A pentachord in music theory may be either of two things. In pitch-class set theory, a pentachord is defined as any five pitch classes, regarded as an unordered collection (Roeder 2001). In other contexts, a pentachord may be any consecutive five-note section of a diatonic scale (Latham 2002). A pe...
   Found op http://en.wikipedia.org/wiki/Pentachord
   
   

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