Most "new" things in computing aren't really new at all, they're just a mystifying wrapper around something that already well-understood. When they're hard to understand, it's usually because someone decided to invent new language terms or colonise existing terms for a different purpose (a good example of that is the X developers' reversal of what "client" and "server" mean.)
Camel is a Java-based wrapper/API for inter-application middleware.
Middleware is a general term for software that provides interpretation services between entities that don't share a common language or data types.
That's what Camel is, at bottom. We can flesh out the description by noting that it provides for EIP-type middleware.
It doesn't provide the middleware itself, since it can't know the details of what the applications need to communicate. But it provides the API for creating the invariant parts of that middleware (create a start point, create an end point, create conditions for starting and ending, etc)
Hope that helps.