Archaic KJV Word
Tree
Modern equivalent: plant
What Was Lost
The narrative arc from Genesis to Revelation. The tree of life appeared in Eden, was lost at the fall, and reappears in Revelation 22 -- its leaves 'for the healing of the nations.' The cross was a tree (Acts 5:30 -- 'whom ye slew and hanged on a tree'). The entire biblical story moves from tree to tree, garden to garden.
Closest Survivor in Modern English
tree of life (still used but as fairy-tale imagery rather than cosmic theology)
Peak Usage (1611)
KJV Genesis 2:9 -- 'The tree of life also in the midst of the garden, and the tree of knowledge of good and evil'
Died still used but de-symbolized (~1700)
Hebrew ets ('tree/wood/the axis mundi connecting heaven and earth/source of life and knowledge') was de-symbolized into a botanical category. Trees in scripture were cosmic symbols connecting creation's beginning to its end.
What Replaced It
“plant”
Biological organism; the tree of life was the source of immortality and the symbol of God's sustaining presence
“timber”
Construction material; the wood of the cross connected back to the tree in Eden
“vegetation”
Ecological category; trees in scripture were the backbone of the cosmic story from Eden to Revelation