Yea

Definition:

(adv.) Yes; ay; a word expressing assent, or an affirmative, or an affirmative answer to a question, now superseded by yes. See Yes.
(adv.) More than this; not only so, but; -- used to mark the addition of a more specific or more emphatic clause. Cf. Nay, adv., 2.
(n.) An affirmative vote; one who votes in the affirmative; as, a vote by yeas and nays.

Compare yea with other words:

affirmative vs. yea