Poin·ca·ré (pw?N-kä-r??), Jules Henri 1854-1912. French mathematician and physicist who made a number of contributions to the fields of celestial mechanics and algebraic topology.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.