pri·mo 
(prēmō)
(prēmō)n. pl. pri·mi (-mē) also pri·mos (-mōz)
Music
Music
The principal part in a duet or ensemble composition.
adj.
1. First.
2. Slang
a. Exceptionally good of its kind; first-class.
b. Highly or most valuable.
[Italian, from Old Italian, first, from Latin prīmus; see per1 in the Appendix of Indo-European roots.]