noun
partial eclipse
Astronomical term for an eclipse where only part of the celestial body is obscured.
今夜は部分月食が見られる。
A partial lunar eclipse can be seen tonight.
部分日食のときは、専用の日食グラスを使わなければならない。
During a partial solar eclipse, you must use special eclipse glasses.
皆既食 means 'total eclipse', where the entire celestial body is covered, as opposed to 部分食 which is only partial.
Compound of 部分 (part, portion) and 食 (eclipse). The kanji 食 is used in astronomical contexts to mean 'eclipse'.