"bottom quark." YourDictionary, n.d. Web. 18 December 2018. <https://www.yourdictionary.com/bottom-quark>.
bottom quark. (n.d.). Retrieved December 18th, 2018, from https://www.yourdictionary.com/bottom-quark
A quark with a charge of −1/3. Its mass is smaller than that of the top quark, but larger than that of all the other quarks. The bottom quark is sometimes referred to as the beauty quark, though this term is falling out of use.