"Despite the fact that; although: He still argues, though he knows he's wrong. Even though it was raining, she walked to work."
"Conceding or supposing that; even if: Though they may not succeed, they will still try. See Usage Note at although.
" However; nevertheless: Snow is not predicted; we can expect some rain, though."
It's no "but" or "however", though it is a useful word, when you want let a reader know that two ideas are opposing one another.