Noun and する verb
いす
この椅子の色違いは置いてますか？
Do you have this chair in any other colors?
A chair child is for some reason just a chair. Not sure why it's a child, but it is.
The reading for 子 is weird. It's す, so think about how you sat on this chair and it broke, so you sued (す) the person who made the chair (who happened to be a child).