Ceviche is a dish made from raw fish that is cooked by a special ingredient called acid. This acid usually comes from citrus fruits like lemons or limes. When you put the raw fish in a bowl and squeeze lemon or lime juice over it, the acid breaks down the proteins in the fish and makes it firm and opaque, just like it's been cooked with heat.
Then, people add other yummy things like chopped onions, tomatoes, cilantro, salt and pepper, to give the ceviche flavor. Sometimes people also add other seafood like shrimp, octopus or squid.
It's super refreshing and perfect for hot days because it's served cold. You can eat ceviche on its own or with crispy tortilla chips. It's a popular dish in Latin America, but it's loved all over the world now!