Webster's Revised Unabridged Dictionary · 1913

Proviso

Proviso , noun

[Latin, (it) being provided, abl. of provisus, past participle of providere. See Provide, and compare Purview.]

An article or clause in any statute, agreement, contract, grant, or other writing, by which a condition is introduced, usually beginning with the word provided; a conditional stipulation that affects an agreement, contract, law, grant, or the like; as, the contract was impaired by its proviso.
He doth deny his prisoners, But with proviso and exception. — Shakespeare