Z configuration:A stereochemical arrangement in alkenes where the two highest priority substituents attached to carbon atoms on either side of a double bond are on the same side.
Cis: trans isomerism - A form of stereoisomerism describing the orientation of functional groups within a molecule across a double bond or ring structure, now largely supplanted by E,Z notation for compounds with more than two substituents.
Priority rules (Cahn: Ingold-Prelog priority rules) - A set of rules used to determine the order of precedence (priority) of groups attached to a chiral center or double bond, crucial for assigning E,Z configurations