n. 1. An abnormal growth of tissue resulting from uncontrolled, progressive multiplication of cells and serving no physiological function; a neoplasm. 2. A swollen part; a swelling: a plant tumor. [Middle English tumour, from Latin tumor, from tumēre, to swell; see teuə- in the Appendix of Indo-European roots.] tumor·al, tumor·ous adj. |
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