pro-E, pro-Z
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 @C01082@ over the other group c, the @S05976@ of the molecule becomes E. The other group c is then described as pro-Z.
PAC, 1996, 68, 2193. (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2214 [Terms] [Paper]