There are spouses, parents, children, siblings, grandparents, grandchildren and cousins. But I know of no gender-neutral word for aunts and uncles. Is there one? For that matter, is there a gendered word for a female or male cousin?
The Spanish might be the best possibility: "primo" for a male cousin; "prima" for a female cousin. According to the ONLINE ETYMOLOGY DICTIONARY (credible source? I don't know; neither my Oxford-American nor my Webster's has the etymology for this word), *cousin* is from Old French *cosin*, from Latin *consobrinus*, which means "mother's sister's child".
I'm far from an expert in German, but knowing their propensity for stringing words together, auf Deutsch, it would be "elterngeschwisterkinder," which translates (I think) to "children of my parents' siblings."
I do not believe there is an equivalent word in English.
I've never said this aloud before, but here's one possible answer to the uncle/aunt part of the question: Â An uncle or aunt is a special case of cousin, specifically, they're one's first cousins once removed (and so are nephews and nieces). Â So I suppose you could fall back on that. Â But no one would understand you, so it's hardly worth mentioning.