tantamount

The story

1. Anglo-Norman · derived fromtant amount
2. English todaytantamount

First attested in English in 1628. Either inherited from an unattested Middle English borrowing from Anglo-Norman tant amount, from amunter, from tant (“as much”) amonter (“to amount to”) or borrowed in the early 17th century from Italian tanto montare (“to amount to as much”).

First known use, by meaning

• 1641– Equivalent in meaning or effect; amounting to the same thing in practical terms, even if being technically distinct.
• 1628–1716 To amount to as much; to be equivalent.
• 1637–1646 Something which has the same value or amount (as something else). (attributive use passing into adjective, below)