| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
| a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes. |
| observable (əb-zûr'və-bəl) Pronunciation Key
A measurable property of a physical system, such as mass or momentum. In quantum mechanics, observables correspond to mathematical operators used in the calculation of measurable quantities. Operators that do not commute, having a nonzero commutator, correspond to observables that cannot be precisely measured at the same time, such as momentum and position. See also uncertainty principle. |