(noun, adjective)


1. capable of being seen or noticed

- an observable change in behavior

Similar word(s): noticeable, discernible, evident


1. (physics) Any physical property that can be observed and measured directly and not derived from other properties

- Temperature is an observable but entropy is derived.

- In quantum mechanics, observables correspond to Hermitian operators. Also, they act a lot like random variables. Taking their average one may recover something resembling a classical observable.