Wiktionary
uncurved
a. Not curved.
WordNet
uncurved
adj. having no curves [syn: uncurving]
Usage examples of "uncurved".
But in any case, if the local gravitational field is effectively the propagating ether, the speed of a traveling disturbance will vary with its density, and the same result can be arrived at by treating it as a refractive medium in uncurved space.