The authors propose the term "proteoform" to describe the various molecular forms of a protein product from a single gene, including genetic variations, alternative splicing, and post-translational modifications. They argue that existing terms like "isoform," "protein species," and "protein variants" are inadequate or confusing. The term "proteoform" is intended to be more comprehensive and precise, covering all forms of protein complexity. The authors have started using this term in their work and believe it will improve clarity and readability in proteomics literature. The proposal is supported by the UniProt Knowledgebase and the wider community, aiming to enhance the understanding of protein variation in both basic and translational research.The authors propose the term "proteoform" to describe the various molecular forms of a protein product from a single gene, including genetic variations, alternative splicing, and post-translational modifications. They argue that existing terms like "isoform," "protein species," and "protein variants" are inadequate or confusing. The term "proteoform" is intended to be more comprehensive and precise, covering all forms of protein complexity. The authors have started using this term in their work and believe it will improve clarity and readability in proteomics literature. The proposal is supported by the UniProt Knowledgebase and the wider community, aiming to enhance the understanding of protein variation in both basic and translational research.