What is the meaning of Yea?

Yes, indeed.

Thus, so (now often accompanied by a hand gesture by way of measurement).

Or even, or more like, nay. Introduces a stronger and more appropriate expression than the preceding one.

Yeah, right, yes.

An affirmative vote, usually but not always spoken

Alternative spelling of yeah

Misspelling of yay.

Alternative form of yee

Source: wiktionary.org