‖ thalamus
(ˈθæləməs)
Pl. -mi (-maɪ). Also (in sense 3) in Gr. form thalamos.
[L. thalamus, a. Gr. θάλαµος an inner chamber.]
1. Anat. A part of the brain at which a nerve originates or appears to originate. Now spec. the optic thalamus (see optic a.).
| [1704 J. Harris Lex. Techn. I, Thalami Nervorum Opticorum, are two Prominences of the lateral Ventricles of the Cerebrum; so call'd, because the Optick Nerves rise out of them.] 1756 Gentl. Mag. XXVI. 517/1 The thalami here appeared very thin, and the pia mater..was overspread with blood-vessels of an unusual size. 1856 Todd & Bowman Phys. Anat. II. 38 Each tract adheres to the outer side of its corresponding thalamus for some distance. 1879 St. George's Hosp. Rep. IX. 513 An abscess..in the right optic thalamus, opening just behind the tænia. 1902 D. J. Cunningham Text-bk. Anat. 501 The two optic thalami, in their anterior two-thirds, lie close together on either side of a deep mesial cleft, which receives the name of the third ventricle of the brain. 1947 Sci. News IV. 112 There is an anatomically distinct region, the thalamus, deep in the brain-stem which has something to do with the perception of pain and other sensations and the judgment of their quality. 1948 A. Brodal Neurol. Anat. vi. 157 It appears..that the thalamus is not only an important relay station in the large afferent sensory fibre systems and the optic and acoustic systems, but in addition extensive parts of it..also discharge their impulses to the cerebral cortex. 1979 Sci. Amer. Sept. 85/2 The rest of the forebrain is the diencephalon: the upper two-thirds comprises the thalamus (which has numerous subdivisions) and the lower third the hypothalamus. |
2. Bot. a. The receptacle of a flower, on which the carpels are placed; the torus. b. See quot. 1842.
| 1753 Chambers Cycl. Supp., Thalamus, in botany, a term used to express that part of the flower..where the embryo fruits..are lodged, and where afterwards the seeds are contained. 1766 Lee Introd. Bot. Gloss., Thalamus,..the Receptacle. 1842 Penny Cycl. XXIV. 274/1 Thalamus is also used in Cryptogamic botany, in common with Thallus, to express the bed of fibres from which many fungi spring up. 1861 Bentley Man. Bot. (1870) 208 The extremity of the peduncle or pedicel..is called the Thalamus, or some times, but improperly, the Receptacle. |
3. Archæol. An inner or secret chamber.
| 1850 J. Leitch tr. C. O. Müller's Anc. Art §48 The thalami, secret chambers for the women. 1884 Times 15 Aug. 4 The same pattern as that found on the roof of the thalamos. |