Word.ws English Dictionary

moly cow

/ˈməʊli kaʊ̯/US/ˈmoʊli kaʊ̯/

moly cow noun: a device used to extract the metastable isotope technetium-99m from a source of decaying molybdenum-99.

moly cow: a device used to extract the metastable isotope technetium-99m from a source of decaying...
Image: Kieran Maher, Public domain, via Wikimedia Commons

Noun

moly cow (plural moly cows)

  1. (informal) A device used to extract the metastable isotope technetium-99m from a source of decaying molybdenum-99.
    • When the ⁹⁹Tcₘ isotope is needed for medical imaging purposes, it has to be created on the spot because its half-life is only six hours. This is done using a device filled with longer-lived ⁹⁹Mo, which decays into ⁹⁹Tcₘ, continually replenishing the supply within the device. Because the process of...2012, Theodore [W.] Gray, The Elements: A Visual Exploration of Every Known Atom in the Universe, New York, N.Y.: Black Dog & Leventhal Publishers, →ISBN
    • The radioactive isotope molybdenum-99 (half-life of 66 hours) decays to generate technetium-99m, which has a half-life of only six hours and is used in hospitals for medical imaging. The technetium isotope collects in various parts of the body, in particular bone. Scanners detect the radiation from...2013, Paul Parsons, Gail Dixon, The Periodic Table: A Field Guide to the Elements, London: Quercus, →ISBN
    Synonyms:
    technetium cow, w:technetium-99m generator

Examples of moly cow in a sentence

  • Because the process of removing the accumulated ⁹⁹Tcₘ is called "milking", the device is informally known as a "moly cow."2012, Theodore [W.] Gray, The Elements: A Visual Exploration of Every Known Atom in the Universe, New York, N.Y.: Black Dog & Leventhal...
  • This is the reason that "technetium generators," dubbed "moly cows," are transported around the globe instead of the ⁹⁹ᵐTc isotope.2013 November 6, Chary Rangacharyulu, “Radioactivity”, in Physics of Nuclear Radiations: Concepts, Techniques and Applications, Boca Raton...

Synonyms of moly cow

Forms of moly cow

pluralmoly cows

Origin of moly cow

Compound of moly (“molybdenum”) (informal) + cow. The term alludes to the fact that the device extracts (“milks”) technetium-99m from molybdenum-99.

Questions about moly cow

What does moly cow mean?
Moly cow means a device used to extract the metastable isotope technetium-99m from a source of decaying molybdenum-99.
How do you use moly cow in a sentence?
Because the process of removing the accumulated ⁹⁹Tcₘ is called "milking", the device is informally known as a "moly cow."
What part of speech is moly cow?
Moly cow is a noun.
How do you pronounce moly cow?
Moly cow is pronounced /ˈməʊli kaʊ̯/ (UK).
What is the plural of moly cow?
The plural of moly cow is moly cows.

Words near moly cow in the dictionary

  1. moluranite
  2. molusc
  3. moluscicidal
  4. Molve
  5. moly
  6. moly cow
  7. moly cows
  8. molybdate
  9. molybdates
  10. molybdatophosphoric
  11. molybdena

Source and license

Adapted from Wiktionary: moly cow (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Pronunciation audio from Wikimedia Commons, each file under its own free license: LL-Q1860 (eng)-Vealhurl-moly cow.wav.

Cite this entry: “moly cow.” Word.ws, https://word.ws/moly_cow. Based on Wiktionary, CC BY-SA 4.0.