Protozoa (n.)

1828, from Modern Latin Protozoa, coined 1818 by German zoologist Georg August Goldfuss (1782-1848) from Greek prōtos "first" (see proto-) + zoia, plural of zoion "animal" (from PIE root *gwei- "to live"). Originally including sponges and corals; current sense is from 1845. Related: Protozoon (singular); Protozoan.