In practice, a relevant charity merger is a charity merger that qualifies for entry on the Register of Charity Mergers so that post‑merger legacies are protected. In England and Wales it is a statutory term in the Charities Act 2011. It broadly covers transactions where one or more charities (the transferors) transfer all property to another charity (the transferee) and the transferor(s) then cease to exist, including conversions to a CIO or the creation of a new successor charity. Registration means gifts in wills and other dispositions to a former charity made after the merger take effect as gifts to the successor, without a cy‑près scheme—simplifying probate, reducing litigation risk and aiding due diligence. The term is commonly used in merger agreements, vesting declarations, legacy administration and regulatory filings, and advisers will check eligibility and arrange timely notification to the Charity Commission. Jurisdictions: the statutory concept and Register of Charity Mergers exist in England & Wales; Scotland has an OSCR register offering similar legacy protection, though terminology differs; Northern Ireland and Ireland have no equivalent statutory register and the expression is not used in the same way.