n. One of several joint signatories to a document.
the GNU version of the Collaborative International Dictionary of English
n. One of several that jointly sign a written instrument, as a treaty.
The Century Dictionary and Cyclopedia
n. One who signs any document jointly with another or others.
Word Usage
"I admire their blasphemous, consignatory, obscenity attitude of acting as if the Great Creator had concocted the whole glorious Universe for their own playground."