Faire son courrier (commercial) = To write one’s letters.
Courroie
Il faut lui serrer la courroie = We must curtail his allowance; We must keep him on short commons.
Faire du cuir d’autrui large courroie = To be generous with other people’s money.
Cours
Les pièces des États du Pape n’ont plus cours = The coins of the Papal States are no longer legal tender.
Un capitaine au long cours = A captain of a trading vessel going to foreign ports.
Court
Je suis resté court = I did not know what to say.