calendar method of birth control

Thesaurus

Noun

1.calendar method of birth control - natural family planning in which ovulation is assumed to occur 14 days before the onset of a period (the fertile period would be assumed to extend from day 10 through day 18 of her cycle)calendar method, rhythm method, rhythm method of birth control, rhythmnatural family planning - any of several methods of family planning that do not involve sterilization or contraceptive devices or drugs; coitus is avoided during the fertile time of a woman's menstrual cycle