Word of the Day:

1 : of, relating to, or having only two experimental alternatives (as dead or alive, all or none)

2 : of or relating to a quantum

The experiment with the herbicide will generate a quantal response -- either the plant to which it is applied will survive, or it will die.

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).