Variant of Adelaide, from Germanic 'adal' (noble) and 'heid' (kind/type), meaning 'noble natured.'
Adalaide is a variant spelling of Adelaide, one of the great Germanic medieval names. It is built from *adal* (noble) and *heid* (kind, type, or nature), producing the meaning "of noble kind" or "noble natured." The name traveled into French as Adélaïde and into English through the Norman conquest, and its alternating spellings — Adelaide, Adalaide, Adalaïde, Adela — reflect centuries of orthographic flux before standardization.
Its most historically significant bearer in the English-speaking world was Adelaide of Saxe-Meiningen (1792–1849), the German princess who married the Duke of Clarence and became Queen of the United Kingdom as consort to William IV. Beloved for her warmth and charitable work, she gave her name to the South Australian capital founded in 1836 — one of the few Australian cities named after a woman. That city has kept Adelaide in the global English-language imagination ever since.
Earlier, Adélaïde of Savoy (1092–1154) was a formidable medieval queen-consort and regent of France, and the name echoed through European royal houses for centuries. The *Adalaide* spelling specifically adds a slight archival quality, as if lifted from a medieval charter or a nineteenth-century family Bible — it looks older and more deliberate than the more familiar Adelaide, which suits parents seeking distinction within a fashionable name. After decades of dormancy, Adelaide-family names surged back in the early twenty-first century alongside Adeline, Adele, and Ada. The slightly unusual double-*a* form of Adalaide gives it individual character within that revival: recognizable but never quite what people are expecting.