mi·cro·dri·li \ˌ ̷ ̷ ̷ ̷ˈdrīˌlī\noun plural Usage: capitalized Etymology: New Latin, from micr- + -drili (from Greek drilos earthworm) in some classifications: a group of Oligochaeta that comprises slender elongated predominantly aquatic worms lacking a capillary network on the nephridium and that is nearly coextensive with Archioligochaeta — compare megadrili