Is it ensure, insure, or assure?
"division of the plant or animal kingdom," 1868, Modern Latin, coined by French naturalist Georges Léopole Chrétien Frédéric Dagobert, Baron Cuvier (1769-1832) from Greek phylon "race, stock," related to phyle "tribe, clan" (see physic). The immediate source of the English word probably is from German.
phylum phy·lum (fī'ləm)
n. pl. phy·la (-lə)
A taxonomic category that is a primary division of a kingdom and ranks above a class in size.
A group of organisms ranking above a class and below a kingdom. See Table at taxonomy.