Chair
noun
A chair child is for some reason just a chair. Not sure why it's a child, but it is.
This is a jukugo word that uses the on'yomi readings of the kanji. But the す reading for 子 here is less common and you haven't really seen it yet, so here's a mnemonic to help you out:
Think about how you broke this chair when you sat on it, so you sue (す) the person who made the chair. (Who happened to be a child, I guess).
この椅子の色違いは置いてますか？
Do you have this chair in any other colors?