BI-RADS (Breast Imaging Reporting and Data System), developed by the American College of Radiology, provides a standardized lexicon and reporting structure for breast imaging including ultrasound. BI-RADS categories range from 0 (incomplete, needs additional evaluation) to 6 (known malignancy). Category 3 indicates probably benign (short-interval follow-up); category 4 is suspicious (biopsy recommended); category 5 is highly suggestive of malignancy. BI-RADS ensures consistent communication between sonographers, radiologists, and clinicians.