Of Germanic origin (via French Adélaïde), from adal ‘noble’ + heid ‘kind, sort’. It was borne in the 10th century by the wife of the Holy Roman Emperor Otto the Great. She became regent after his death and was revered as a saint. The given name increased in popularity in England during the 19th century, when it was borne by the wife of King William IV; she was the daughter of the ruler of the German duchy of Saxe-Meiningen. The Australian city of Adelaide was named in her honour.
English: topographic name for someone who lived by a rocky crag or outcrop, from Old French roche (later replaced in England by rock, from the Norman byform rocque), or a habitational name from any of the places named with this word, such as Roach in Devon, or Roche in Cornwall and South Yorkshire.