As the title suggests, what, exactly, do we call the individual Stack Exchange sites? I've spent a while thinking about it and can't come up with an answer. Stacklets? Stacks? Exchangelets? Subexchanges? Is there an official name we use? It's odd that I've never seen the sites spoken of in this way, but I'm sure it's come up at least once in conversation.
Note: This is not a duplicate of this question: What are the "proper" names for Stack Exchange sites? which is clearly very different.