Wiktionary
n. 1 (context sciences English) A field of science such as physics or chemistry which is capable of accurate quantitative expression or precise predictions and rigorous methods of testing hypothesis. 2 (context figuratively usually as “not to be exact science” English) A situation in which the same outcome follows from similar beginnings.
Usage examples of "exact science".
Pryor's reformulation of the General Field Theory did away with Heisenberg's Uncertainty Principle, physics has been considered an exact science.
That worked once, with that ant-like race on Medusa, and it was played up by the ERB politicians until now most of the Supreme Council believes the ERB claim that relations with alien life forms has been reduced to an exact science by the ERB and the slow methods of the Frontier Corps are worthlessly obsolete.
Like other forms of public relations, keeping public order is not an exact science.