特征速度是表征推进剂能量大小及其在燃烧室中的燃烧效率的参数，具有速度量纲。推进剂能量愈高，在燃烧过程中能量转换效率愈高，则值愈大。

其中

是特征速度，

是燃烧室压强，

是喷喉横截面积，

是发动机质量流率。

Characteristic velocity or , or C-star, pronounced "see star," is a measure of the combustion performance of a rocket engine independent of nozzle performance, and is used to compare different propellants and propulsion systems.