Expert elicitation is when grown-ups ask people who are really good at something for advice. It's almost like asking a superhero for help!
Say you're building a new playground and you want to make sure it's safe. You might ask an expert on playground safety - someone who knows everything there is to know about making sure kids don't get hurt - to give you some ideas on what you can do to make your playground super safe.
Sometimes, experts might not agree on what the best thing to do is. So, grown-ups might ask lots of different experts to give their opinions. Then, they take all the different ideas and decide what's most important and what will work best for the project they're working on.
This way, by asking experts for their opinions, grown-ups can make sure they're doing the best possible job - just like a superhero helping out the good guys!