ジュウ, チョウ, え, おも.い, おも.り, おも.なう, かさ.ねる, かさ.なる, おも, さね, しげ, しげる
heavy, heap up, pile up, nest of boxes, -fold
JLPT4 G3 S9 F193
The relevant seal inscription form is 東# (run through) + a person standing on the ground → the *weight* of a person thrusting down heavily on the earth, as though to run through it → *heavy*; *pile up*; *be piled upon*. Extended meanings include *fold*, *ply*, *occur simultaneously*, *do repeatedly* and *place weight on/attach importance to* → *value highly*; *importance*; *important*. Also, *depressing* and *serious* (← heaviness/weightiness).
[Full Kanji Etymology List]