mentumn.
/ˈmɛntəm/, U.S. /ˈmɛn(t)əm/ 1. Anatomy and Zoology. The anterior and inferior margin of the mandible (lower jaw); the chin.
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the world > life > the body > external parts of body > head > face > chin > [noun]
chinc1000
mentum1693
1693 tr. S. Blankaart Physical Dict. (ed. 2) 139 Mentum, the Chinn.
1835 R. D. Hoblyn Dict. Terms Med. & Collateral Sci. 140/1 Mentum, the chin.
1865 W. T. Brande & G. W. Cox Dict. Sci., Lit., & Art II. 495/1 Mentum, in Mammalogy, this term is restricted to the anterior and inferior margin of the mandible, or lower jaw. The mentum prominulum is that which extends beyond the perpendicular line dropped from the upper margin of the lower jaw.
1985 M. F. Myles Textbk. Midwives (ed. 10) xxii. 381 There are six positions in face presentation: denominator the mentum.
1994 Okajimas Folia Anat. Japonica 71 227 The shape from alveolus to mentum changes from a flat waveform..to two bumps.
2. Entomology. Originally: any of various parts of the labium. Later: spec. the anterior part of the base of the labium in certain insects.
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the world > animals > invertebrates > phylum Arthropoda > class Insecta > parts of insects > [noun] > head > mouth-parts or trophi > part of labium
mentum1826
1826 W. Kirby & W. Spence Introd. Entomol. III. 355 Mentum, the lower part of the labium, where it is jointed; in other cases its base.
1826 W. Kirby & W. Spence Introd. Entomol. III. 356 (note) Our [sc. the authors'] Mentum may generally be known by its situation between the hinges and base of the Maxillæ.
1828 J. Stark Elements Nat. Hist. II. 281 Mentum large; maxillary palpi long.
1888 G. Rolleston & W. H. Jackson Forms Animal Life (ed. 2) 141 A palpiger borne on the external angle of the mentum.
1938 A. D. Imms Gen. Textbk. Entomol. (ed. 4) i. 21 In many Orthoptera a distal sclerite or mentum is developed immediately behind the labial suture.
1994 P. J. Gullan & P. S. Cranston Insects ii. 34/1 There are two main parts to the labium—the proximal postmentum,..sometimes subdivided into a submentum and mentum, and the free distal prementum.
3. Botany. In certain tropical genera of orchids: a chinlike projection formed by the attachment of the lateral sepals to the foot of the column (column n. 7).
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1866 J. Lindley & T. Moore Treasury Bot. II. 735/2 Mentum, a projection in front of the flowers of some orchids, caused by the extension of the foot of the column.
1900 B. D. Jackson Gloss. Bot. Terms 155/2 Mentum, an extension of the foot of the column in some Orchids, in the shape of a projection in front of the flower.
1976 Hortus Third (L. H. Bailey Hortorium) 369/2 Dendrobium Swartz. Orchidaceae... Lateral sepals forming a distinct mentum with column foot.
1984 European Garden Flora II. 201/3 Masdevallia... Column toothed at apex; column foot forming a short mentum with base of lateral sepals.
This entry has been updated (OED Third Edition, September 2001; most recently modified version published online March 2022).
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