Subject
Noun and の adjective
わだい
友だちと話題のフグをかいに行きました。
We went to buy the much-talked-about fugu.
明くる朝、オフィスに行くと、コウイチのけっこんしきとよく日の電げきりこんの話題で持ちきりだった。
When I went to the office the next morning, everyone was talking about Koichi's wedding and his sudden divorce on the following day.
ここまでは理解していただけたかと思うのですが。それでは、次の話題に移りましょうか。トマトは、原産地が南米なだけでなく、フグの一番好きな野菜でもあるってことは知っていましたか？
I hope you’ve understood so far. All right, now let’s move on to the next topic. Did you know tomatoes are not only native to South America but they’re also Fugu’s favorite vegetable?
The topic that we are talking about is the topic that we are talking about. It's the subject of our conversation.
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.