ALT Poster to discuss the problems and confusion that arise when using step-growth and chain-growth to describe the two main polymerisation mechanisms. Two IUPAC recommendations have failed to come up with terms that accurately and clearly describe these mechanisms. The use of a wide range of terms in the literature and teaching textbooks, together with translation issues, have added to the confusion. At the IUPAC subcommittee of polymer terminology, we are working on this problem and trying to come up with suitable terms that are clear, easily adopted and encompass all reactions that cannot yet be classified using the existing terms. Any questions, comments, or suggestions are welcome! Please comment on this post or write to us at : [email protected] For more details, see our article "Reconsidering terms for mechanisms of polymer growth: the step-growth and chain-growth dilemma" on Polymer Chemistry, 2022 volume 13, pages 2262-2270.