The Web Services Choreography Description Language (WS-CDL) was a specification by W3C of a language that describes a [choreography].
The members of the Working Group described it as follows:
The Web Services Choreography Description Language (WS-CDL) is an XML-based language that describes peer-to-peer collaborations of participants by defining, from a global viewpoint, their common and complementary observable behavior; where ordered message exchanges result in accomplishing a common business goal.
The effort to standardize WS-CDL was abandoned in 2009, leaving v1.0 as a 'candidate recommendation' only.
The WS-CDL is of interest to the PL community, because the Working Group invited many PL experts from academia to contribute to the effort (including Robin Milner, Kohei Honda, Nobuko Yoshida, and Marco Carbone).
WD-CDL Version 1. This is the last specification released by the group in 2005, four years before it disbanded.
The W3C maintains a page on the history of WS-CDL Working Group, which also contains a list of invited experts.