substagen.
/ˈsʌbsteɪdʒ/, U.S. /ˈsəbˌsteɪdʒ/ 1. A subdivision of a stage. Chiefly in Geology, with reference to stratigraphic and glacial stages: cf. stage n. 1i.
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1849 Amer. Jrnl. Sci. 57 50 We have shown..how the American substages should be grouped to correspond with the Silurian, Devonian and Carboniferous systems of Europe.
1859 C. Darwin Origin of Species ix. 297 If the specimens come from different sub-stages of the same [geological] formation.
1906 T. C. Chamberlin & R. D. Salisbury Geol. III. 383 The following are the American stages of the glacial period now recognized in the interior of North America... The Champlain sub-stage (marine). The glacio-lacustrine sub-stage.
1952 W. J. Miller Introd. Hist. Geol. (ed. 6) xxiv. 457 Most of the loess was deposited during an early Wisconsin sub-stage.
1985 Cambr. Encycl. Life Sci. i. 39/1 The first meiotic prophase..usually takes longer than all the other stages put together. It is conventionally divided into five substages.
2006 D. H. Erwin Extinction ix. 221 Not until the Spathian, the last of the four substages of the Early Triassic..is there a demonstrable increase in speciation.
2. Microscopy. A fitting located beneath the ordinary stage of a microscope in order to support a condenser or other accessory. Frequently attributive.
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the world > physical sensation > sight and vision > optical instruments > magnification or magnifying instruments > [noun] > microscope > parts of
object plate1664
slider1703
pout1832
indicator1837
substage1853
focuser1861
nosepiece1867
searcher1870
Abbe condenser1879
eyeshade1885
1853 Trans. Microsc. Soc. London 1 83 Mr. Ross has constructed a very comprehensive microscope-stand, furnished with right-lined and circular motions, not merely to the stage but to what may be called the sub-stage, or that part which carries the different illuminators for transparent objects.
1878 Nature 16 May 65/2 It works admirably with Powell and Lealand's ordinary sub-stage condenser.
1892 H. C. Bumpus Lab. Course Invertebr. Zoöl. 124 The sub-stage is generally provided with a perforated apparatus—the diaphragm—for limiting the amount of light.
1906 A. L. Winton Microsc. Veg. Foods 7 It consists of two Nicol prisms, one (the polarizer) mounted in the substage, the other (the analyzer) in the tube or above the eye-piece.
1979 Sci. Amer. Jan. 126/2 Bell achieves this kind of illumination by angling his mirror so that the substage condenser..causes the light to converge on the specimen.
2004 W. D. Nesse Introd. Optical Mineral. (ed. 3) ii. 23/1 The substage can be raised and lowered.
This entry has been updated (OED Third Edition, June 2012; most recently modified version published online March 2022).
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