, whereas cancer is by definition malignant. Etymology The term tummor is derived, via the Old French tumour, from the Latin tumor "swelling". It originally meant an abnormal swelling of the flesh. In contemporary English, tumor is synonymous with solid neoplasm, all other forms of swelling being called swelling. This usage is common also in medical literature, where the nouns tumefaction and tumescence, derived from the adjective tumefied, are the current medical terms for non-neoplastic swelli… (More on Tumor)