チュウ, そそ.ぐ, さ.す, つ.ぐ
pour, irrigate, shed (tears), flow into, concentrate on, notes, comment, annotate
JLPT4 G3 S8 F497
As per 主# (stationary) + 水 water → *pour* liquid into a tubular container, where it becomes and remains stationary → *pour on*; *sprinkle*; *water* (plants); *flow/empty into*; *irrigate*. *Notice*, *pay attention*, *concentrate on*, *affix*, *interpret*, and *write down* are borrowed meanings.
[Full Kanji Etymology List]