tect

‖n. pl. [ NL. ] Same as Tectibranchiata. [ 1913 Webster ]

‖n. pl. [ NL., fr. L. tectus (p. p. of tegere to cover) + Gr. &unr_; a gill. ] (Zool.) An order, or suborder, of gastropod Mollusca in which the gills are usually situated on one side of the back, and protected by a fold of the mantle. When there is a shell, it is usually thin and delicate and often rudimentary. The aplysias and the bubble shells are examples. [ 1913 Webster ]

a. [ L. tectus (p. p. of tegere to cover) + E. branchiate. ] (Zool.) Having the gills covered by the mantle; of or pertaining to the Tectibranchiata. -- n. A tectibranchiate mollusk. [ 1913 Webster ]

adv. [ L. tectus covered, fr. tegere to cover. ] Covertly; privately; secretly. [ Obs. ] Holinshed. [ 1913 Webster ]

n. [ Gr. &unr_; a carpenter + -logy. ] (Biol.) A division of morphology created by Haeckel; the science of organic individuality constituting the purely structural portion of morphology, in which the organism is regarded as composed of organic individuals of different orders, each organ being considered an individual. See Promorphology, and Morphon. [ 1913 Webster ]

a. [ L. tectonicus, Gr. &unr_;, fr. &unr_;, &unr_;, a carpenter, builder. ] 1. Of or pertaining to building or construction; architectural. [ 1913 Webster ]

2. (Biol.) Structural. [ Webster 1913 Suppl. ]

3. (Geol. & Phys. Geog.) Of, pert. to, or designating, the rock structures and external forms resulting from the deformation of the earth's crust; as, tectonic arches or valleys; tectonic plates. [ Webster 1913 Suppl. +PJC ]

n. 1. The science, or the art, by which implements, vessels, dwellings, or other edifices, are constructed, both agreeably to the end for which they are designed, and in conformity with artistic sentiments and ideas. [ 1913 Webster ]

2. (Geol. & Phys. Geog.) the branch of geology concerned with the rock structures and external forms resulting from the deformation of the earth's crust; also, similar studies of other planets. Also called structural geology. [ PJC ]

plate tectonics a geological theory which considers the earth's crust as divided into a number of large relatively rigid plates, which move relatively independently on the more plastic asthenosphere under the influence of magmatic upwellings, so as to drift apart, slide past, or collide with each other, causing the formation, breakup, or merging of continents, and causing volcanism, the building of mountain ranges, and the subduction of one plate beneath another. In recent decades a large body of data have accumulated to support the theory and provide some details of the mechanisms at work. One set of supporting observations consists of data showing that the continents have slowly moved relative to each other over long periods of time, a phenomenon called continental drift. Africa and South America, for example, have apparently moved apart from a connected configuration at about 2 to 3 cm per year over tens of millions of years. [ PJC ]

a. [ L. tectorius. ] (Anat.) Of or pertaining to covering; -- applied to a membrane immediately over the organ of Corti in the internal ear. [ 1913 Webster ]