noun
phase of an eclipse; magnitude of an eclipse
Technical astronomy term for the fraction of the diameter of a celestial body that is eclipsed. Used in contexts like solar or lunar eclipses.
今回の月食の最大食分は1.2です。
The maximum magnitude of this lunar eclipse is 1.2.
食分が大きいほど、日食は暗くなります。
The larger the eclipse magnitude, the darker the solar eclipse becomes.
Compound of 食 (eclipse) and 分 (part, fraction). The exact historical derivation is uncertain, but the term is used in modern astronomy.