Sentence:  For while we are used to simply dividing modes internally in terms of fifths and fourths to make an octave, Jacques complicates matters for us by introducing concepts from the monochord in Liber V, thus <WSD>enneachords</WSD> and decachords, i.e ranges of nine and ten notes. 
Meaning of the word marked with <WSD> tags:  A musical interval of nine notes.