The period in the menstrual cycle during which conception is most likely to occur, usually 10 to 18 days after the onset of menstruation.
10 Commonly Misused WordsSome words have taken on incorrect meanings over time through consistent misuse. Make sure you're using the right word.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.