Proviso, stipulation, caution, a condition, inserted in any deed, on the performance whereof the validity of the deed depends. As to the proviso for re-entry in a lease, see FORFEITURE (5); CONDITION; USUAL COVENANTS.
The terms proviso and condition are synonymous, and signify some quality annexed to a real estate by virtue of which it may be defeated, enlarged, or created upon an uncertain event. Such qualities annexed to personal contracts and agreements are generally called conditions. A proviso or condition differs from a covenant in this, that the former is in the words of, and binding upon, both parties; whereas the latter is in the words of the grantor only. At the same time a proviso or condition may be construed as a covenant or agreement if the proviso involves the consideration upon which the benefit is obtained a fortiori, where words such as 'provided that, and it is hereby agreed' are used. But if no intention that the proviso was intended to be obligatory can be gathered from the deed or contract the proviso merely amounts to a qualifica-tion of the grant or promise. See Halsbury, L.E., tit. 'Interpretation of Deeds.'