Though (tho), conj.
Etymology: [OE. thogh, þah, AS. edheáh, edhæh, edheh; akin to OS. thoh, OFries. thach, D. & G. doch but, yet, OHG. doh but, yet though, Icel. þo yet, nevertheless, Sw. dock, Dan. dog, Goth. þáuh, þáu, than, or, yet; of uncertain origin. 184.]
Granting, admitting, or supposing that; notwithstanding that; if. Though he slay me, yet will I trust in him. Job xiii. 15. Not that I so affirm, though so it seem. Milton.
Note: It is compounded with all in although. See Although. As though, as if. In the vine were three branches; and it was as though it budded. Gen. xl. 10.
1 other Webster entry under this spelling
Though, adv.
However; nevertheless; notwithstanding; -- used in familiar language, and in the middle or at the end of a sentence. I would not be as sick though for his place. Shak. A good cause would do well, though. Dryden.
Shades of meaning
Fernald has no entry of its own for though; he lists it under notwithstanding.
He lists it without comment; the entries above explain its neighbors.