Billings method
noun
- a system for finding the time of ovulation by examining cervical mucus. It can be used as a form of birth control by avoiding sexual intercourse at that time.比林斯排卵期测定法（通过检查宫颈黏液测定排卵期, 在该时期内避免房事可达到避孕目的）。
词源
1960s: named after Drs John and Evelyn Billings, who devised the method.