observable

adj

1. Able to be observed.

   “The strange new star was at the edge of the observable universe.”

   “In 1913, in the same year that Mother's Day became a nationally observable holiday, the American people passed another milestone: for the first time in American history more than one person in one thousand was divorced.”

   “Although intellectual property rights, such as patents, are highly observable, they are mostly limited to product technologies. Process technologies, or the routines endemic in the firm's production, are not readily observable, and thus cannot be easily imitated.”

2. Deserving to be observed; worth regarding; remarkable.

   “Both were observable figures; one a personable individual of foreign cut, the other—obviously in spite of his well-wrapped-up form—a pronounced cripple.”

noun

1. 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 expected value one may recover something resembling a classical observable.”