"The cat is a pet."
Translation:Кошка — домашнее животное.
I've seen the word питомец used to refer to a pet in several places online. The Wiktionary entries for that word also seem to suggest that it refers to a pet. Is this a colloquial word, or does it carry connotation which makes it more specific than the more generic домашнее животное?
"домашняя" should apply to "животное" (not to the cat: The cat is a domestic animal, so domestic modifies animal, not cat), so it is "домашнее" (because animal is neuter).
Also, "животных" is the genitive plural (also the accusative plural since it is an animated noun). Here the simple nominative singular "животное" is expected.