Orchestration - The art of writing, arranging, or scoring for the orchestra.
Perfect cadence - The chordal progression of dominant to tonic, in a major key V-I, in minor V-i.
Refrain - A short section of repeated material which occurs at the end of each stanza.
Score - The written depiction of all the parts of a musical ensemble with the parts stacked vertically and rhythmically aligned.
Tenuto, ten - Hold or sustain a note longer than the indicated value, usually not as long a duration as the fermata.