trinomial
Concise Oxford English Dictionary © 2008 Oxford University Press:
trinomial /trʌɪˈnəʊmɪəl/
▶adjective
- 1 (of an algebraic expression) consisting of three terms.
- 2 Biology (of a taxonomic name) consisting of three terms where the first is the name of the genus, the second that of the species, and the third that of the subspecies or variety.
'trinomial' also found in these Oxford entries:

