spīˈriləm noun
Etymology: New Latin, diminutive of Latin spira coil, twist — more at spire
1. capitalized : a genus of bacteria formerly coextensive with the family Spirillaceae but now restricted to elongated forms having tufts of flagella at one or both poles and usually living in stagnant water rich in organic matter — compare rat-bite fever , vibrio
2. pl spiril·la -lə
a. : any bacterium of the genus Spirillum or of the group to which it belongs — compare spirillaceae
b. : spirochete