[kaashif]

On the other hand, I've never heard of uncle meaning any family member other than the brother of a parent.

At the very least, we can agree that using "uncle" like this is incredibly easily misinterpreted.

[tristor]

Meanwhile, I refer to one of my father’s second cousins as my uncle. It completely depends on context, even in more strict cultures around this. If someone is close enough to the family they can be an aunt or uncle even if their relation is more distant.

[joelfried]

I'm a bit surprised you've never heard of the spouse of a parental sibling called an uncle as well. To make that more explicit: my father's sister is my aunt, and her husband is my uncle.

[flufferstutter]

That is definitely common in my experience. Now calling the brother of my parent’s brother’s wife “uncle” might be a bit of stretch.

[kaashif]

Oh, I meant brother in law too, actually. But my point is, anything beyond that isn't something I've heard.

[gambiting]

In my family every single male relative is an uncle(and every female is an aunt).