In simple terms: an ovary with many small follicles or increased ovarian volume on ultrasound.
Why it matters for PCOS
A polycystic ovarian appearance means ultrasound finds many small follicles (under the Rotterdam criteria, at least 20 in one ovary) or an ovarian volume above 10ml. These follicles are not true cysts but immature eggs whose development stalls when ovulation does not happen regularly. This appearance is one of the three Rotterdam criteria for PCOS, alongside irregular periods and signs of high androgens.
A polycystic appearance on its own does not confirm PCOS, because it can also show up in healthy young women with no other symptoms. For an accurate follicle count, a transvaginal ultrasound is clearer than a transabdominal one. Your doctor reads this finding together with your cycle pattern, symptoms, and hormone results.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.