'Malignant tumor' definitions:

Definition of 'malignant tumor'

noun

A tumor that is malignant and tends to spread to other parts of the body [syn: malignant tumor, malignant neoplasm, metastatic tumor]

From: GCIDE

Tumor \Tu"mor\ (t[=u]"m[~e]r), n. [L., fr. tumere to swell: cf. F. tume['u]r. See Tumid.]
1. (Med.) A morbid swelling, prominence, or growth, on any part of the body; especially, a growth produced by deposition of new tissue; a neoplasm. [1913 Webster]
2. Affected pomp; bombast; swelling words or expressions; false magnificence or sublimity. [R.] [1913 Webster]
Better, however, to be a flippant, than, by a revolting form of tumor and perplexity, to lead men into habits of intellect such as result from the modern vice of English style. --De Quincey. [1913 Webster]
Encysted tumor, a tumor which is inclosed in a membrane called a cyst, connected with the surrounding parts by the neighboring cellular substance.
Fatty tumor. See under Fatty.
Innocent tumor, or Benign tumor, one which does not of itself threaten life, and does not usually tend to recur after extirpation; a tumor which has not metastesized.
Malignant tumor, a tumor which tends continually to spread, to become generalized in different parts of the body, and to recur after extirpation, and which, if left to itself, causes death. [1913 Webster]

From: GCIDE