To Stack, To Pile Up, To Accumulate
transitive verb, ichidan verb
You've got lots of heavy things, so the only logical thing is to stack them all up. Besides heavy physical things, you can also use this word when you're going to accumulate things like experience, practice, or years on your back.
かさねる
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: All the things you've stacked up were in preparation for your new casa (かさ). With everything inside boxes and neatly piled up, you're finally ready to move into your new casa. Hooray!
そんなにお皿を重ねると危ないですよ。
It is dangerous to stack so many plates.
プリンセスは、年を重ねるごとに美しくなっていきました。
The princess became more and more beautiful as she grew older.
答えのないことにディスカッションを重ねるのってムダじゃないですか？
Isn't it a waste of time to have a bunch of discussions about things that don't have answers?