-ectomy: A surgical suffix referring to the removal of something. For example, a lumpectomy is the surgical excision of a lump which may be benign or not, tonsillectomy is the removal of the tonsils, a partial colectomy is removal of part of the colon, an appendectomy is removal of the appendix, etc. From the Greek "ek" (out) + "tome" (a cutting) = a cutting out.