darm·stadt·i·um (därm?shtät??-?m)n. Symbol Ds An artificially produced radioactive element with atomic number 110. Isotopes having mass numbers ranging from 267 to 281 are known, with the most stable isotope (Ds-281) having a half-life of about 10 seconds. See Periodic Table.[After Darmstadt.]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.darmstadtium (d??m?stæt??m) n (Elements & Compounds) a synthetic radioactive element produced in small quantities by cold fusion in a linear accelerator. Symbol: Ds; atomic no: 110[C21: named after Darmstadt, where it was discovered]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014