Any of various gram-negative, coccoid microorganisms of the genus Chlamydia, especially C. psittaci and C. trachomatis, that are pathogenic to humans and other animals, causing conjunctivitis in cattle and sheep and trachoma, urethritis, and proctitis in humans.
Any of several common, often asymptomatic, sexually transmitted diseases caused by the microorganism Chlamydia trachomatis.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.