This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
An aett entry records one of the three families of eight runes that divide the twenty four rune Elder Futhark, the oldest fully attested runic alphabet, used across Germanic speaking Europe from around the second century of the common era onward. The threefold division survives on the Kylver Stone, a funerary marker from Gotland in Sweden dated to around 400 CE, whose carved rune row is separated into three blocks of eight by a set of dots, giving the earliest datable physical evidence that the alphabet was already grouped this way rather than treated as one unbroken sequence.
An entry records an aett's position within the row, first, second or third, its eight member runes in their attested order, and the name later tradition gives the group, Freyr's Aett, Heimdall's Aett or Tyr's Aett, a naming convention that comes from later interpretive sources rather than from any surviving inscription, since no Elder Futhark carving itself explains why the three blocks bear the names they do.
Michael Barnes' handbook lays out this epigraphic record, the Kylver Stone among its worked examples, as the settled starting point for any claim about how the row was organized, distinct from the divinatory or elemental readings later esoteric systems have built on top of that plain archaeological fact.