KJV Dictionary Definition: yea
YEA, adv. Ya.
1. Yes; a word that expresses affirmation or assent. Will you go? Yea. It sometimes introduces a subject, with the sense of indeed, verily, truly, it is so.
Yea, hath God said, ye shall not eat of every tree in the garden? Genesis 3.
Let your communication be yea, yea; nay, nay. Matthew 5.
2. It sometimes enforces the sense of something preceding; not only so, but more.
Therein I do rejoice; yea, and will rejoice. Philippians 1.
3. In Scripture, it is used to denote certainty, consistency, harmony, and stability.
All the promises of God in him are yea, and in him are amen. 2 Corinthians 1.
In this use, the word may be considered a noun.
Yea is used only in the sacred and solemn style. See Yes.