Dictionary.com

mesothorium

[ mez-oh-thawr-ee-uhm, -thohr-, mes-, mee-zoh-, -soh- ]
/ ˌmɛz oʊˈθɔr i əm, -ˈθoʊr-, ˌmɛs-, ˌmi zoʊ-, -soʊ- /
Save This Word!

noun Chemistry.
one of two radioactive decay products of thorium, an isotope of radium or actinium.
QUIZ
CAN YOU ANSWER THESE COMMON GRAMMAR DEBATES?
There are grammar debates that never die; and the ones highlighted in the questions in this quiz are sure to rile everyone up once again. Do you know how to answer the questions that cause some of the greatest grammar debates?
Question 1 of 7
Which sentence is correct?
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

British Dictionary definitions for mesothorium

mesothorium
/ (ˌmɛsəʊˈθɔːrɪəm) /

noun
physics obsolete either of the two radioactive elements which are decay products of thorium. Mesothorium I is now called radium-228. Mesothorium II is now called actinium-228
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
FEEDBACK