universal Turing machinen. A Turing machine that can do the work of any possible Turing machine and is thus powerful enough to perform any calculation, given enough time and memory. Also called universal computer, universal machine.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.