For alkenes and similar double bonded molecules, the same prioritizing process is followed for the substituents. In this case, it is the placing of the two highest priority substituents with respect to the double bond which matters. If both high priority substituents are on the same side of the double bond, i.e. in the "cis" configuration, then the stereoisomer is assigned a "Z" ("zusammen") . If by contrast they are in a "trans" configuration, then the stereoisomer is assigned an "E" ("entgegen"). In this case the identifying letters are derived from German for 'together' and 'opposite', respectively.