Keep, Hold, Maintain, Retain
noun, verbal noun
When you preserve the things you hold on to, you're keeping them. In other words, you're holding and maintaining them! Note that 保持 is a formal word that's commonly used in professional or official contexts.
ほじ
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
高いクオリティを保持するのは工場にとって大切なことです。
It is important for the factory to maintain high quality.
今年も全米タイトルを保持しました。
I retained the US title this year too.
データは一ヶ月保持された後は、全てなくなります。
The data will be preserved for one month, then it will be gone.