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n. pl. di·rec·trix·es or di·rec·tri·ces (dī′rĕk-trī′sēz)
1. Mathematics A fixed curve traversed by a generatrix in generating a conic section or a cylinder.
2. The median line in the trajectory of fire of an artillery piece.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. (Mathematics) geometry a fixed reference line, situated on the convex side of a conic section, that is used when defining or calculating its eccentricity
2. (Professions) a directress
[C17: New Latin, feminine of director]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
di•rec•trix(dɪˈrɛk trɪks, daɪ-)
n., pl. di•rec•trix•es, di•rec•tri•ces (dɪˈrɛk trɪˌsiz, daɪ-, ˌdaɪ rɛkˈtraɪ siz)
1. a fixed line used in the description of a curve or surface.
2. Archaic. directress.
usage: See -trix.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
A straight line used in constructing a curve such as a parabola.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.