Catholic to you means the Roman Catholic Church.
To Christians it means the universal church of those who follow Christ.
Again, in debating with Roman Catholics a set of agreed upon definitions is required as Rome likes to redefine common words to sometimes mean other than what they are.
The Catholic Church has been using these terms in a variety of languages for a millennium before the English Language even came into existence.
We certainly have the right to define these words when we're talking about Catholicism.
Surely you can see that.