Noun bacteria has 1 sense
  1. bacteria, bacterium - (microbiology) single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission; important as pathogens and for biochemical properties; taxonomy is difficult; often considered plants
    --1 is a kind of microorganism
    --1 has particulars:
     acidophil, acidophile; bacteroid; Calymmatobacterium, genus Calymmatobacterium; Francisella, genus Francisella; gonococcus, Neisseria gonorrhoeae; Legionella pneumophilia, legionella; nitrobacterium; penicillin-resistant bacteria; rod; diplococcus; Rickettsia