Definition of "correus"

When a creditor will accept ſolutionem particularum vel correi, the debtor or the correus muſt pay

1656 June 7, John Thurloe (author) and Thomas Birch (editor), “A letter of intelligence from the Hague, 7 June 1656” in A Collection of the State Papers of John Thurloe V (London, 1742), page 71

Since this act, few take bonds with cautioners, but bind them all as correi and principals.

1707 December 17, Sir John Lauder of Fountainhall (editor), The Deciſions of the Lords of Council and Seſſion, from June 6th, 1678, to July 30th, 1712 II (Edinburgh, 1761), page 404