All 10 Uses

although
in
Zero Day
(Auto-generated)

That fact had triggered CID involvement, although he wasn't sure why the case had landed in the lap of the 701st.†
p. 15.5

although = even though -- used to connect contrasting ideas
Go do it now, although the guy's probably long gone.†
p. 81.9
Behind the counter were rows of coffee pots that, despite the late-night heat, were in continuous use—although Puller saw many bottles and drafts of cold beer circulated to the thirsty patrons too.†
p. 86.3
He also saw what was in the man's hand, although Frank was trying to hide it.†
p. 126.3
The cops climbed out of their rides and stood at semi-attention, although Puller interpreted far more contempt in their body language than respect for a superior officer.†
p. 130.4
To his older sibling Puller was either "bro" or sometimes "Junior"—although lately the latter term had not been used by him very much because it was a reminder of their father.†
p. 370.1
You can use the gun method, which is not good at all, although the first A-bomb dropped on Japan used that design.†
p. 371.7
It wasn't like he was going to stay around for the mushroom cloud, although he didn't bother taking his grieving wife.†
p. 427.9
Although, I do think we might conveniently lose the footage of you taking the Russian and Mason out.†
p. 431.5 *
Although he had always thought there would be other times with the woman.†
p. 433.2

Definitions:

(1) (although)
even though -- used to introduce an idea that contrasts with or makes the main statement surprising

At the start of a sentence, although can play a role similar to words like however, yet, still, even so, on the other hand, or nonetheless—all of which signal contrast. In the middle of a sentence, although can sometimes be used where but or though might also work, but though or but often sound more natural. For example, "She's a great teacher, though not the most popular" is usually smoother than "She's a great teacher, although not the most popular."
(2) (meaning too rare to warrant focus)