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safe period

American  

noun

  1. an interval of the menstrual cycle when fertilization is considered to be least likely, usually a number of days prior and subsequent to the onset of menstruation.

safe period British  

noun

  1. informal the period during the menstrual cycle when conception is considered least likely to occur See also rhythm method

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of safe period

First recorded in 1915–20

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.