In simple terms: the release of a mature egg from the ovary, usually once per menstrual cycle.
Why it matters for PCOS
Ovulation happens when a mature follicle releases an egg, triggered by a surge in luteinising hormone (LH). This opens the fertile window, the time when conception is most likely. In PCOS, hormonal imbalance can disrupt follicle maturation, so ovulation may happen rarely or not at all (anovulation). This is the main reason periods become irregular and fertile windows are hard to predict.
Ovulation can be confirmed by a doctor through a progesterone blood test or ultrasound monitoring, rather than assumed from period dates alone. Restoring regular ovulation is often a treatment goal for women with PCOS who are planning a pregnancy.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.