IMPORTANCE: Previous editions of the International Glossary on Infertility and Fertility Care (2006, 2009, 2017) established internationally recognized definitions related to clinical practice, research, and policy. The 2017 edition comprised 283 terms and, among many other changes, expanded the definition of infertility to include not only its recognition as a disease causing disability, but also as resulting from an impairment of a person's capacity to reproduce either as an individual or with his/her partner. The glossary has been extensively used worldwide and has contributed to international standardization of data collection, appropriate comparison of outcome measures, and provided a reference for all stakeholders, including policy makers. Updates are now required to reflect contemporary scientific knowledge, social needs, and inclusive definitions, while harmonizing international communication across clinical, research, policy, and public domains OBJECTIVE: To update the latest International Glossary on Infertility and Fertility Care, 2017 to reflect current scientific knowledge, evolving social contexts, and inclusive terminology, thereby promoting harmonized international communication across clinical, research, policy, and public domains. EVIDENCE REVIEW: Under guidance of the organizing committee, 21 professionals from across the world representing expertise in different sub-specialties formed five working groups: clinical definitions; outcome measures; embryology laboratory; clinical and laboratory andrology; and epidemiology, public health and gender related definitions. The definitions from the previous glossary were evaluated and new terms identified. All definitions were then reviewed by an international advisory panel of nine experts that evaluated the glossary from scientific, ethical, cultural, and policy perspectives. Following several virtual discussions and a one-day in-person meeting, most terms and definitions were agreed. In the absence of agreement, further discussions were held between the organizing committee, working group chairs and members of the advisory panel. It had been determined at the outset that final disagreement would be resolved via a two-thirds majority vote. All terms and definitions were, however, reached by consensus and adopted following a final round of review and approval by all authors. FINDINGS: The glossary now includes 348 terms. Compared to the previous edition, 14 terms were deleted, numerous terms were modified and 79 new terms were added. Modifications reflect current scientific knowledge, technological advancements, and inclusivity related to gender and family structures. CONCLUSIONS AND RELEVANCE: This updated glossary provides a global reference for standardized terminology, supporting clinical care, research, international comparisons, policy making, patient communication, and reproductive health literacy. Periodic updates will be required as scientific and societal contexts evolve.