Bacterium

//bækˈtɪəɹ.ɪəm// noun

noun ·Moderate ·College level

Definitions

Noun
  1. 1
    A single-celled organism with cell walls but no nucleus or organelles.

    "Plastics are energy-rich substances, which is why many of them burn so readily. Any organism that could unlock and use that energy would do well in the Anthropocene. Terrestrial bacteria and fungi which can manage this trick are already familiar to experts in the field."

  2. 2
    (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 to be plants wordnet

Synonyms

All synonyms
bugamebicamoebaanaerobebacillusbacteria

Example

More examples

"The toxin that causes diphtheria is produced by a normally benign bacterium when infected with a certain virus."

Etymology

From New Latin bactērium, from Ancient Greek βακτήριον (baktḗrion, “small staff”), from βακτηρία (baktēría).

Related phrases

Hansen’s bacteriumblue-green bacteriumgreen bacteriumiron bacteriummirror bacteriumpurple sulfur bacteriumsulfur bacteriumsulphur bacteriumcell wallssingle celled

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.