I like Lemony Snicket's approach: he gives (obviously) wrong, but technically correct, definitions for hard words. These definitions are usually hyper-specific, or satirical. Children, who are still very familiar with learning vocabulary from context, can find this much more amusing than adults who have given up on learning new words except via dictionaries.

> The word “briskly” here means “quickly, so as to get the Baudelaire children to leave the house.”

> “Wipi!” Sunny shrieked, which meant “I’d much prefer gardening to sitting around watching my siblings struggle through law books.”