Archaic KJV Word
Treasure
Modern equivalent: valuable possessions
What Was Lost
The heart-diagnostic. 'Where your treasure is, there will your heart be also' was not financial advice but a spiritual X-ray. Your treasure was whatever owned your heart -- whatever you organized your life around. Finding your treasure revealed your functional god. The parable's man sold everything for the kingdom because he recognized the ultimate treasure.
Closest Survivor in Modern English
treasure (still used but heard as 'valuable stuff' rather than 'the thing that owns your heart')
Peak Usage (1611)
KJV Matthew 6:21 -- 'Where your treasure is, there will your heart be also'; Matthew 13:44 -- 'The kingdom of heaven is like unto treasure hid in a field'
Died still used but monetized (~1900)
Hebrew otzar and Greek thesauros ('treasure/storehouse/the accumulated wealth of what you value most/what defines your ultimate allegiance') monetized into 'money and valuables.' The allegiance-diagnostic dimension was lost.
What Replaced It
“money”
Currency; treasure was whatever you valued so much it controlled your life's direction
“valuables”
Material possessions; treasure was the thing that captured your heart and defined your identity
“wealth”
Financial; treasure was whatever functioned as your de facto god