In Its Entirety
Whole, Wholly, Entirely
adverb
If you go to (ごと) a circle, you need to go to it in its entirety. That means you have to circle around the whole thing. Otherwise, it isn't even a circle. It's like a line or a squiggle or something.
まるごと
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You learned this reading, so you should be able to read this too!
わたしは、そのうたを丸ごとあんきしています。
I’m memorizing the whole song.
その牛、半分だけじゃなくて丸ごと一とう下さい。
Please give me the whole cow, not half.
このケーキには林檎が丸ごと入っています。
This cake is filled entirely with apples.