Fatness
Vine's Expository Dictionary of NT Words [1]
from pion, "fat," from a root, pi---, signifying "swelling," is used metaphorically in Romans 11:17 . The gentile believer had become a sharer in the spiritual life and blessing bestowed by Divine covenant upon Abraham and his descendants as set forth under the figure of "the root of (not 'and') the fatness of the olive tree."
King James Dictionary [2]
FAT'NESS, n. from fat.
1. The quality of being fat, plump, or full fed corpulency fullness of flesh.
Their eyes stand out with fatness. Psalms 73 .
2. Unctuous or greasy matter. 3. Unctuousness sliminess applied to earth: hence richness fertility fruitfulness.
God give thee of the dew of heaven, and the fatness of the earth, and plenty of corn and wine. Genesis 27 .
4. That which gives fertility.
Thy paths drop fatness. Psalms 65 .
The clouds drop fatness.
5. The privileges and pleasures of religion abundant blessings.
Let your soul delight itself in fatness. Isaiah 55 .
Webster's Dictionary [3]
(1): ( n.) Hence; Richness; fertility; fruitfulness.
(2): ( n.) The quality or state of being fat, plump, or full-fed; corpulency; fullness of flesh.
(3): ( n.) That which makes fat or fertile.
International Standard Bible Encyclopedia [4]
fat´nes ( דּשׁן , deshen ; πιότης , piótēs ):
1. Literal
The translation of deshen ( Judges 9:9 , "But the olive-tree said unto them, Should I leave my fatness?"; Job 36:16 (of food)), "full of fatness"; of ḥēlebh , "fat," "the best part," "the marrow" ( Job 15:27; Psalm 73:7; Isaiah 34:6 , Isaiah 34:7 ); of mishmān , "fatness," "fertility" ( Genesis 27:28 , "the fatness of the earth"; Isaiah 17:4 , "the fatness of his flesh"); of shemen , "fatness," "oil" ( Psalm 109:24 ); of piotēs , "fat," "fatness" ( Romans 11:17 , "partaker ... of the root of the fatness of the olive tree").
2. Figurative
"Fatness" is used figuratively for the richness of God's goodness; as such it is the translation of deshen ("They shall be abundantly satisfied (margin "Hebrew watered") with the fatness of thy house" ( Psalm 36:8 ); "Thy paths drop fatness" ( Psalm 65:11; compare Isaiah 55:2; Jeremiah 31:14 ).
"With fatness" is supplied, Deuteronomy 32:15 the King James Version, "covered with fatness"; the Revised Version (British and American) has "become sleek"; for "The yoke shall be destroyed because of the anointing" ( Isaiah 10:27 ) the American Standard Revised Version has "by reason of fatness," margin "Hebrew oil"; the English Revised Version as the King James Version, with margin as the American Standard Revised Version; the text is believed to be corrupt; Septuagint has "from your shoulders."