The Russian translation for "pet" is домашнее животное, in this case meaning a domesticated animal one keeps in one's home. To a native English-speaker that seems like quite a bookish term. Admittedly this question is tinged with a cultural bias, but is there any commonly-used colloquial or slang word that can be used as an alternative?
Update: I'm aware that домашнее животное does not literally mean "pet", it's just the most common translation I've seen for the word "pet". That was the main impetus for my question -- not having seen another way to translate it, and wondering if there was a more colloquial term.