a very small parasitic bacterium which, like a virus, requires the biochemical mechanisms of another cell in order to reproduce. Bacteria of this type cause various diseases including trachoma, psittacosis, and non-specific urethritis.
Genus Chlamydia and order Chlamydiales
1960s: modern Latin (plural), from Greek khlamus, khlamud- 'cloak'
chlamydia in other Oxford dictionaries
Definition of chlamydia in the US English dictionary