Some people do all their best thinking in the shower or in the bathroom, my Little Man does his in the car:
LM: What does "died" mean?
Me: (freaking out a little) Um, I guess it means that the person or thing is not alive any more?
Me: Well, when you are alive, your heart is beating and your brain is working, and your body is moving... When you aren't alive, everything stops. Um, do you think you can you ask me about this again in a couple years? Maybe I will be more prepared...
LM: Um, sure Mom, you are so clever.
Me: Thanks, buddy. You are too!