postulate

/ˈpɑsʧəˌleɪt/

(logic) a proposition that is accepted as true in order to provide a basis for logical reasoning

中文释义：假定；基本假设

The theory is based on the postulate that all matter is composed of atoms.

该理论基于所有物质由原子组成这一假设。

Einstein's postulate of the speed of light revolutionized physics.

爱因斯坦关于光速的假设彻底改变了物理学。