NOUN (2)

1. a sexually transmitted infection caused by bacteria of the genus Chlamydia;

2. coccoid rickettsia infesting birds and mammals; cause infections of eyes and lungs and genitourinary tract;

The Collaborative International Dictionary of English v.0.48:

chlamydia \chlamydia\ n.
   a coccoid rickettsia which may infect birds and mammals; it
   causes infections of eyes and lungs and the genitourinary
   tract.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

chlamydia
    n 1: a sexually transmitted infection caused by bacteria of the
         genus Chlamydia
    2: coccoid rickettsia infesting birds and mammals; cause
       infections of eyes and lungs and genitourinary tract