Tacticity is a term that refers to the arrangement of monomer units in a polymer chain. However, there are several synonyms for the word tacticity that are often used in polymer science. One of the synonyms for tacticity is stereochemistry, which refers to the study of the 3D structure of molecules. Another synonym for tacticity is Geometric Isomerism, which pertains to the structural variation of chemical compounds. Isotacticity is another synonym for tacticity and refers to the polymer chains that are made up of monomers that are all oriented in the same direction. Other synonyms for tacticity include regiochemistry, chirality, and conformation. These terms are all important in understanding the structure and properties of polymers.