Previously, Before
noun
From before, just means previously or before now.
いぜん
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.
あの男の人は、以前会ったことがある人です。
That man is someone I've met before.
以前は、シドニーによく来ていました。
Before, I used to come to Sydney often.
２０００年以前のアクティブファンドのパフォーマンスは、今よりずっといいんですよ。
Active fund performance before the year 2000 was much better than it is now.