Concise Bible Dictionary:

Joy, or gladness, is what man craves and is set upon finding; and he does find it when he finds God, and only then. He retains it too in proportion as he grows in the knowledge of God. God is the author of true joy as of every good and perfect gift. Being Himself perfectly good and above all evil, He is even represented as finding His own joy in the repentance of the sinner who returns to seek Him. Sin having come in, and man being thus, alas, alienated from God, his idea of joy is to be as happy as he can make himself without God and away from Him. (See the prodigal in Luke 15) But disappointment and bitterness here and eternal sorrow hereafter alone can result from such a course as that. When however, on the contrary, the light of God’s love, revealed in the gift and the death of His Son, breaks upon the heart, it is filled at once “with joy unspeakable and full of glory.”
“The kingdom of God is not meat and drink; but righteousness, and peace, and joy in the Holy Ghost.” The fruit too of the Spirit is love, joy, peace, with other beautiful traits, and this is produced in the believer’s heart by the Spirit for God’s glory. The apostle desired for the Romans that the God of hope would fill them with all joy and peace in believing (Rom. 15:1313Now the God of hope fill you with all joy and peace in believing, that ye may abound in hope, through the power of the Holy Ghost. (Romans 15:13)). The Thessalonians too had received the word in “much affliction with joy of the Holy Ghost.” Many more passages might be cited to show how joy is one of the leading characteristics of those who have been brought to know God. The one only Man who never had to be so brought—because His delight was ever in God, as God’s was in Him: He who is called a “man of sorrows”—this perfect and blessed One had His own deep joy in communion with and in dependence upon God; and He desires for His own in the world that this His joy might be theirs.
True joy is unknown in the world in its present state; but there is a day coming when sorrow, suffering, death, and all the gloomy fruits of sin, will be done away, and God Himself will wipe away all tears and fill the universe with joy unclouded and eternal. That day is depicted in Revelation 21.

Strong’s Dictionary of Hebrew Words:

(Aramaic) corresponding to 2304
KJV Usage: