potty-train 
verb [with object]
Train (a small child) to use a potty: he’s just been potty-trained...
- Also worth looking out for are novelty chamber pots often made in the form of animals which were designed to potty-train small children.
- It's important not to punish potty-training children or show disappointment when they wet or soil themselves or the bed.
- Some parents try desperately to potty-train their children much too young, and may think not only that they have succeeded, but also that they, the parents, have made a great achievement.