su·​per·​heavy ˌsü-pər-ˈhe-vē How to pronounce superheavy (audio)
: extremely heavy
superheavy furniture
superheavy traffic
a superheavy discussion with his mother
especially, chemistry : relating to or being a chemical element with a greater atomic mass than that of uranium
The existence of superheavy elements, those with many more protons than uranium (proton number 92), was predicted more than 40 years ago. Georg Bollen
superheavy noun
plural superheavies
In February the world was treated to a transcontinental eureka moment: Scientists … announced they had discovered two new chemical elements. Called superheavies because of their large atomic mass, elements 113 and 115 lasted little more than a second. Elizabeth Svoboda

Examples of superheavy in a Sentence

Recent Examples on the Web Imitating a black hole’s causal powers requires an actual superheavy object, not just computer code. Christof Koch, Scientific American, 8 Sep. 2023 The researchers’ mathematical analysis showed how any object with mass—and not just a superheavy one such as that of a black hole—affects the pairs of particles and antiparticles that emerge from the vacuum of space. Adam Mann, Scientific American, 22 June 2023 Patience is key in the superheavy world because the vast majority of collisions in the reactor produce unwanted nuclei, and a vanishing few, if any, are superheavy elements. Adam Hadhazy, Discover Magazine, 22 Jan. 2015 Much technical work remains, but the company appears to be well on its way to delivering a superheavy-lift rocket that is fully reusable, low-cost, and potentially capable of delivering as much as 100 tons to the surface of most bodies in the Solar System. Eric Berger, Ars Technica, 1 Dec. 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'superheavy.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1822, in the meaning defined above

Time Traveler
The first known use of superheavy was in 1822

Dictionary Entries Near superheavy

Cite this Entry

“Superheavy.” Dictionary, Merriam-Webster, Accessed 22 May. 2024.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!