I never claimed it would be language-agnostic. It's a Modern Perl OO book. I just hope that it can teach principles that they can apply when programming in other languages too.

With the wrong terminology?

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}

Wikipedia says

The term delegation is also used loosely for various other relationships between objects; see delegation (programming) for more. Frequently confused concepts are simply using another object, more precisely referred to as consultation or aggregation; and evaluating a member on one object by evaluating the corresponding member on another object, notably in the context of the receiving object, which is more precisely referred to as forwarding (when a wrapper object doesn't pass itself to the wrapped object).12a The delegation pattern is a software design pattern for implementing delegation, though this term is also used loosely for consultation or forwarding.

So the terminology might be considered imprecise by Wikipedia, but as that terminology and use is far from uncommon, I guess you'll have to rely on the exact definitions given by each writer instead of hoping for a general terminology.