tesseractrepresented in two dimensionstes·ser·act (t?s??-r?kt?)n. A four-dimensional hypercube.[Greek tessera, neuter pl. of tesseres, four; see tessera + akt?s, ray of light; see actino-.]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.tesseract (?t?s??rækt) n (Mathematics) maths a cube inside another cubeCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014