[a. L. tūber neut., a hump, swelling, pl. tūbera.]
1. Bot. An underground structure consisting of a solid thickened portion or outgrowth of a stem or rhizome, of a more or less rounded form, and bearing ‘eyes’ or buds from which new plants may arise; a familiar example is the potato. Also applied to other underground structures resembling this but of different origin, as in tuberous roots.
1668. Wilkins, Real Char., 90. Tuberous roots; consisting of one single tuber, or of several.
1704. [see b].
1822. J. Flint, Lett. Amer., 57. The potato crops are better…, the plants are more vigorous, and the tubers much larger.
1870. Hooker, Stud. Flora, 352. Orchis. Tubers globose ovoid or palmate.
1880. Gray, Struct. Bot., iii. § 3 (ed. 6), 59. A Tuber may be … characterized as a short thickened rhizoma on a slender base, or a rootstock some portion of which … is thickened by the deposition of nourishing matter.
ǁ b. A genus of underground discomycetous fungi, comprising the truffles.
[1693. Phil. Trans., XVII. 824. The Tubera Terræ … observ’d lately at Rushton in Northamptonshire … are indeed the true French Truffles, the Italian Tartuffi.
1699. Evelyn, Acetaria, 42. Trufles, Pig-Nuts, and other subterraneous Tubera.]
1704. J. Harris, Lex. Techn., I. Tuber, properly, is a subterraneous Mushroom, or a Truffle; but by Botanick Writers, is often used to signifie the round turgid Roots of some Plants: which they call Tuberose, or Knobby Roots.
2. A rounded swelling or protuberant part in the animal body. a. Path. A morbid swelling or enlargement, as of a gland, etc.
1706. Phillips (ed. Kersey), Tuber,… a Swelling or Bunch in a Man’s Body.
1834. Good’s Study Med. (ed. 4), IV. 233. Those who are constitutionally predisposed to a production of tubers and tubercles.
1888. Fagge & Pye-Smith, Princ. Med. (ed. 2), I. 96. In a solid organ it [i.e., a tumour] may form a rounded mass, which is called a nodule or tuber.
b. Anat. A rounded projecting part or structure; a tuberosity.
Chiefly as Latin, with pl. tubera: often with defining word, as the specific name of such a structure: e.g., tuber cinereum, a conical projection at the base of the brain; tuber cochleæ or tympani, the promontory of the tympanum.
1741. Monro, Anat. (ed. 3), 209. The Tuber is afterwards added in the Manner that other Epiphyses are.
1857. Dunglison, Med. Lex., Tuber cinereum, a grayish tubercle, seen at the base of the brain behind the commissure of the optic nerves.
1866. Huxley, Preh. Rem. Caithn., 110. Norwegians are remarkable for the length of their skulls, and the very general development of an occipital tuber, or probole.
3. gen. A rounded projection, protuberance. rare.
1888. Doughty, Arabia Deserta, I. 32. We … came where in a torrent bed are laid bare certain great tubers of the lime rock underlying.
