Allen

Allen is an English given name derived from the Celtic name Alan, whose exact root meaning is debated but is most often interpreted as either little rock or harmony. The name was brought to England by Breton followers of William the Conqueror during the Norman Conquest of 1066, helping establish it as a common medieval English surname and given name. It has long been used interchangeably with Alan and Allan, and all three forms remain in use across English-speaking countries today.