Archaic KJV Word
Tithe
Modern equivalent: required donation
What Was Lost
The ownership declaration. Tithing was not generosity -- it was recognition that the first tenth belonged to God because everything belonged to God. It was a trust exercise: giving the firstfruits before you knew if there would be enough, declaring by action that God owned it all and you trusted Him with the rest.
Closest Survivor in Modern English
tithe (still used in Christian traditions but often experienced as 'paying a bill' rather than 'worshipping through giving')
Peak Usage (1611)
KJV Malachi 3:10 -- 'Bring ye all the tithes into the storehouse'; Genesis 14:20 -- 'He gave him tithes of all'
Died still used but bill-ified (~1900)
Hebrew maaser ('tenth/firstfruits recognition that everything belongs to God') reduced from a joyful act of worship and trust to 'the church's bill' -- an obligation rather than a declaration of divine ownership.
What Replaced It
“donation”
Voluntary gift of your money; tithe was returning God's portion of what was already His
“church dues”
Membership fee; tithe was a worship act declaring God as owner of everything
“offering”
Generic; tithe was specifically a tenth -- precise, disciplined, and first-off-the-top