Then cat is female
Yes, when referring to a cat in general, Germans use the female form "Die Katze". If you're referring to a special male cat you would use "Der Kater" instead.
Danke! That's the answer I came here to ask for. :)
I am still quite confused on which der, die, das To use at which times ??
You just have to memorize them. There are some rules but they have many exceptions.
How do you define whether "Eine Katze" is "One cat" or "A cat"?
In writing, only context makes it clear.
In speech, ein/eine is usually stressed when it means "one" and unstressed when it means "a(n)".