ab initio

The story

1. Latin · borrowed fromab initiō“from the beginning”
2. English todayab initio

Unadapted borrowing from Latin ab initiō (“from the beginning”), from ab (“from”) + initiō, ablative singular of initium (“beginning”).

First known use, by meaning

• Early 17ᵗʰ century. From the time when a law, legal right or decree, contract, ownership interest, partnership (etc.) comes into force.