charta de una parte

from Bouvier's Law Dictionary, Revised 6th Ed (1856)

CHARTA DE UNA PARTE. A deed of one part; a deed poll. 
     2. Formerly, this phrase was used to distinguish, a deed poll, which is 
an agreement made by one party only, that is, only one of the parties does 
any act which is binding upon him, from a deed inter partes. Co. Litt. 229. 
Vide Deed poll; Indenture; Inter partes.