pro-E, pro-Z

https://doi.org/10.1351/goldbook.P04867
One of a pair of identical groups c attached to a double bond (as in abC=Cc2) is described as pro-E if, when it is arbitrarily assigned @[email protected] over the other group c, the @[email protected] of the molecule becomes E. The other group c is then described as pro-Z.
Source:
PAC, 1996, 68, 2193. (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2214 [Terms] [Paper]