You aren’t my real child.
When that Russian kid grew up she got better than a salmon at swimming upstream.
Don’t you think my kid looks similar to Beyoncé?
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it uses the kun'yomi reading. When learning the kanji, you didn't learn that reading, so here's a mnemonic to help you with this word:
You see a child and walk up to him. Then, you punch him in the face (oh no, how could you!!?). He flies through the air, and he's knocked out. A ref nearby yells that it was a "KO!" (こ). That's a knock out.
Make sure you learn this reading pretty well too. Both readings for 子 are going to show up a lot, and this is how you're going to learn the kun'yomi one.