Risk is what you can put a probability on (i.e., quantify). Uncertainty is what you can't. Uncertainty encompasses unknown unknowns. See Knight[1] and Keynes[2

Risk is what you can put a probability on (i.e., quantify). Uncertainty is what you can't. Uncertainty encompasses unknown unknowns. See Knight[1] and Keynes[2]. Good rule of thumb even if it sounds overly simplified. [1]: https://www.econlib.org/library/Knight/knRUP.html https://www.econlib.org/library/Knight/knRUP.html [2]: https://www.jstor.org/stable/4538116 https://www.jstor.org/stable/4538116