Hat, Cap
noun
A hat child is a hat or cap. Sadly, it's not made from children, unless you're crazy.
ぼうし
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
こないだ海でフグって名前のめちゃくちゃ大きい男に会ったんだけど、その人シルクハットみたいな帽子被っててさぁ、…あ、そういう感じの帽子、分かる？
The other day I met this ridiculously big man named Fugu in the ocean and he was wearing something that looked like a top hat, you know that kind of hat?