A breast lump is biopsied: invasive ductal carcinoma, grade 2, stage II. The words decode prognosis: carcinoma (epithelial origin), invasive (malignant — breached basement membrane; in situ would be contained), grade 2 (moderately differentiated — how abnormal cells look), stage II (tumor size + few nodes, no distant spread — how far it went). Treatment follows staging (surgery ± chemo/radiation); grading refines risk. Nomenclature is the oncologist's shorthand — every syllable a decision.