Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ----(OR) ----

Ovulation is the release of a single, mature egg from a follicle that developed in the ovary. It usually occurs regularly, around day 14 of a 28-day menstrual cycle. Once released, the egg is capable of being fertilized for 12 to 48 hours before it begins to disintegrate. This is the most fertile period of your cycle: during ovulation your chances of conception are highest.

Luteal phase, also referred to as 'days past ovulation' or 'DPO', is the part of the cycle that starts at ovulation and ends the day before your next period. It usually lasts about 14 days and does not vary by more than a day in each person. The luteal phase is named after the corpus luteum (Latin: "yellow body"), a structure that grows on the surface of the ovary where a mature egg was released at ovulation. The corpus luteum produces progesterone in preparing the body for pregnancy. Your luteal phase must be at least 10 days long to support pregnancy.