A butterfly with another butterfly added to it? It's still a butterfly, just a really big one with... with four wings. And laser eyes? Oh well, just go with it. It's a butterfly.

While 蝶 is the formal word for butterfly you'll see in advanced books or science stuff, 蝶々 is the everyday version you'll actually say out loud. The repetition just makes it sound a little cuter, you know? It kind of… flutters off the tongue.

The reading is just the on'yomi readings (which you learned with the kanji) twice in a row. Easy!

In real conversation, though, the last う usually gets dropped, so people say it as ちょうちょ instead of ちょうちょう. Same butterfly, just a little lighter on the wings.