Large Amount
Large Sum
noun, の adjective
A many amount is a large amount or large sum.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
会社は多額の投資を行って新しい製品を開発したが、失敗に終わった。
The company invested a large amount of money in developing a new product, but it ended in failure.
私は多額の借金を負ってしまったことを、まだ家族に言えずにいます。
I still haven't told my family that I have accumulated a large amount of debt.
最終的に会議はうまくいって、なんとか我々の科学調査への多額の寄付金を約束してもらうことができたよ。
In the end the meeting went smoothly, and we managed to make them promise us a large donation for our scientific research.