#0020 ἀγαλλίασις agalliasis {ag-al-lee'-as-is}

 from G0021; TDNT - 1:19,4; n f

—Greek Word Study (Transliteration-Pronunciation Etymology & Grammar)

 1) exultation, extreme joy, gladness

 At feasts, people were anointed with the "oil of gladness". Paul, in
 He. 1:9, is alluding to this inaugural ceremony of anointing, and
 uses it as an emblem of the divine power and majesty to which to
 which the Son of God has been exalted.

—Thayer's (New Testament Greek-English Lexicon)

—Strong's (Greek Dictionary of the New Testament)

—NAS Exhaustive Concordance of the Bible with Hebrew-Aramaic and Greek Dictionaries

 AV - gladness 3, joy 1, exceeding joy 1; 5

—Exhaustive Concordance (KJV Translation Frequency & Location)