Rainey is an English and Scottish surname that goes back to the medieval name Reynold or Rainier, from the Germanic ragin, "counsel", and heri, "army"; most modern parents simply hear the word "rain" in it. The blues singer Ma Rainey, the "Mother of the Blues", gives the name a proud American pedigree. Rainey has climbed from number 3583 in 2015 to number 2137 in 2022, its best rank, and stands at number 2376 among girls' names in 2025.