Definition of tumor in English:

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Pronunciation: /ˈt(y)o͞omər/
(British tumour)


1A swelling of a part of the body, generally without inflammation, caused by an abnormal growth of tissue, whether benign or malignant.
Example sentences
  • One of the commonest reasons for undertaking a biopsy is to establish whether a tumour is malignant or benign.
  • Both benign and malignant tumors showed ulceration of the overlying mucosa.
  • Malignant brain tumors grow and spread into neighboring tissues rapidly.
cancerous growth, malignant growth, cancer, malignancy;
lump, growth, swelling, fibroid;
Medicine  carcinoma, sarcoma
1.1 archaic A swelling of any kind.



Pronunciation: /ˈt(y)o͞om(ə)rəs/
Example sentences
  • Neither ductal nor lobular carcinoma in situ were found in multiple sections of both tumorous and nontumorous breast tissue.
  • A 19-year-old man presented with a tumorous swelling of the left 10th rib of approximately 1 year's duration.
  • Hamartoma is a tumorous lesion that consists of anomalously arranged tissues that are components of the normal structure of origin.


Late Middle English: from Latin tumor, from tumere 'to swell'.

For editors and proofreaders

Syllabification: tu·mor

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