date of execution; agreement date; entering date
Used in legal and business contexts for the date a contract, treaty, or agreement is formally concluded or comes into effect.
The execution date of the contract is the first of next month.
Please confirm the date of conclusion of the treaty.
Compound of 締結 (conclusion, signing) and 日 (day). The exact historical derivation is uncertain, but the word follows a common pattern for formal date terms.