Science, Tech, Math › Science Why Is a Mole in Chemistry Called a Mole? Share Flipboard Email Print The unit "mole" comes from the word "molecular" and not the furry rodent. Ekaterina79, Getty Images Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated July 06, 2019 A mole is an important unit in chemistry. Do you know the mole got its name? No, it's not named for the burrowing animal! Here is the answer to why a mole is called a mole. Key Takeaways: How the Mole Units Got Its Name The mole is a unit used in chemistry that is equal to Avogadro's number. It is the number of carbon atoms in 12 grams of the isotope carbon-12.The word mole comes from the word molecule. It is not related in any way to the animal called the mole.The mole is most often used to convert between numbers of atoms and molecules to the gram mass unit. Ostwald is responsible for coming up with the term "mole" (Mol), although his original unit was defined in terms of the gram. His later writings made it clear he intended this unit to be based on the ideal gas concept. Around 1900, Ostwald wrote, "...the molecular weight of a substance, expressed in grams, shall henceforth be called mole [. . . das in Grammen augedruckte [. . .] Molekulargewicht eines Stoffes soll fortan ein Mol heissen]" "That amount of any gas that occupies a volume of 22414 mL in normal conditions is called one mole [eine solche Menge irgendeines Gases, welche das Volum von 22412 ccm im Normalzustand einnimt nennt man ein Mol]" Moles even have their own day, aptly named Mole Day. References Ostwald, W. Grundriss der allgemeinen Chemie; Leipzig: Engelmann, 1900, p. 11.Ostwald, W. Grundriss der allgemeinen Chemie, 5th ed.; Dresden: Steinkopff, 1917, p. 44.