Okay kiddo, so a collop is just a fancy word for a small, thin slice of meat. You know when we cut slices off a big piece of chicken or beef for dinner? Those slices are collops!
People use collops a lot when they're cooking fancy meals, like at a fancy restaurant or for a special occasion. They might put a few collops on a plate and decorate them with pretty vegetables or sauces to make them look really special.
So basically, collops are just another way of saying slices of meat. Hope that helps!