AM
Morning, A.M.
noun
You have something that's before (or in front of) noon. What is before noon? That is AM.
ごぜん
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.
このデパートは、午前十じにひらきます。
This department store opens at 10:00 am.
わたしのむす子は、まだ午前中にあさねをするひつようがあります。
My son still needs to take a nap in the morning.
今日は午前9時にテレパシーで投稿する予定にしているので、もし君がその時何か面白いことを考えたら、それは私の仕業だから。
I’ll be posting telepathically at 9AM today, so if you think of something funny, that was me.