quantal

Merriam-Webster's Word of the Day for February 7, 2009 is: quantal • \KWAHN-tul\  • adjective 1 : of, relating to, or having only two experimental alternatives (as dead or alive, all or none) 2 : of or relating to a quantum Examples: The experiment with the herbicide will generate a quantal response -- either the plant to which it is applied will survive, or it will die. Did you know? In Latin, "quantum" is the neuter form of "quantus," meaning "how much?" Both of these forms played a role in the development of "quantal." The first sense of "quantal," used in scientific experimentation to refer to cases in which only one of two possible results occurs, derived from "quanti," the plural of "quantus." ("Quantus" is also an ancestor of our noun "quantity.") The second sense of "quantal" is more directly related to Latin "quantum" and the English noun "quantum," which refers to the smallest possible unit of a form of energy (such as light). See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.