1. A surgical operation for breast cancer in which the surgery is limited to the removal of the visible and palpable tumor only: "A lumpectomy is not a mastectomy during which the breast is removed."

"Lumpectomies are rapidly gaining acceptance because in many cases it can save lives without the disfigurement of mastectomy."

2. The surgical removal of a small tumor (a lump) which may or may not be benign or malignant: "Lumpectomy has come to refer especially to the removal of a lump from the breast."

"Except for the lump's removal, lumpectomies leave the breast intact."

3. Etymology: The word lumpectomy is a hybrid term. "Lump" is of Middle English origin while -ectomy comes from two Greek roots ek, "out" + tome, "a cutting" = "a cutting of"; so, a lumpectomy is literally "a cutting out of a lump".