I was just process a pattern for the shop - Alice Brooks 7241 - which calls for use of Corde. Now, I've a fair number of patterns that call for Corde and have searched numerous times for equivalents, with no success to speak of. BUT, this pattern lists two alternatives that I thought I'd pass along here ....

1 strand of corde =
4 strands of Mercerized Crochet and Knitting Cotton held together, or
Double strand of Sports Yarn

Hope someone might find this of assistance.