1. A recurrent viral disease caused by the herpes simplex virus, type one, and marked by the eruption of fluid-containing vesicles on the mouth, lips, or face.
2. A recurrent viral disease caused by the herpes simplex virus, type two, and marked by the eruption of fluid-containing vesicles on the genitals.

[New Latin herpēs simplex : Latin herpēs, herpes + Latin simplex, simple.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.