Any member of the crustacean family Daphnidae, which includes water fleas and similar small aquatic organisms.
From Daphnia, the genus name, plus the biological suffix -id used for members of a family or group. Became standardized in biological nomenclature in the 20th century.
Daphnids are among the most studied organisms in biology—they're so small and simple that scientists can watch evolution happen in real time, with generations passing every few weeks!
Complete word intelligence in one call. Free tier — 50 lookups/day.