BBT mean Basal Body Temperature
One of the changes that ordinarily take place in a woman’s body as part of her menstrual pattern is that her body temperature is lower during the first part of the cycle. In most women it usually rises slightly with ovulation and remains up during the second part until just before her next period. Recording each day’s basal body temperature helps to indicate when ovulation has occurred.
it mean basal body temperature.and you can chart it by taking ur temperature everry morning same time before doing anything (either going to wc). that help to know when the ovulation occur.