‘乳癌’ is a compound noun meaning ‘breast cancer’ — a malignant tumor that develops in breast tissue. The first character, 乳 (rǔ), means ‘breast’ or ‘milk’, referring to the anatomical location; the second, 癌 (ái), means ‘cancer’ and is used in all medical terms for malignant tumors (e.g., 肺癌 ‘lung cancer’, 胃癌 ‘stomach cancer’). Together, they form a standard, formal medical term widely used in clinical settings, public health campaigns, and media reports in Chinese-speaking regions.

This word is neutral in register but carries serious connotations due to its medical gravity. It’s commonly encountered in discussions about screening (e.g., 乳房X光检查), risk factors (e.g., 家族史), prevention, and treatment. Unlike colloquial or euphemistic expressions (e.g., 乳腺疾病 ‘breast disease’), 乳癌 is precise and unambiguous — preferred in professional and educational contexts over vague or softened alternatives.