The system built around Enochian Fam is a more layered, later thing than the letter's origin in Edward Kelley's reported visions, recorded in John Dee's diaries between 1582 and 1589 and discussed elsewhere in this atlas. Dee himself organised the material Kelley brought him into a Great Table of angelic names governing four quarters he called Watchtowers, but it was the Hermetic Order of the Golden Dawn, active from the 1890s, that added a fuller correspondence system on top of Dee's own work, assigning each Watchtower one of the four classical elements and linking the whole structure to the tarot and the zodiac in ways Dee's own writing never spelled out.
Aleister Crowley, once a Golden Dawn initiate, later put the Enochian Calls to a very different use in 1909, scrying through what he termed the thirty Aethyrs in a series of sessions published as The Vision and the Voice, a personal application of the material well beyond either Dee's angelic conversations or the Golden Dawn's own elemental framework. Whatever weight the wider Enochian system carries in modern ceremonial magic, Fam itself remains simply one letter among twenty-one, its meaning bound up in the Calls that use it rather than in any property of the letter standing alone.
Sources The Golden Dawn: The Original Account of the Teachings, Rites, and Ceremonies of the Hermetic Order of the Golden Dawn, 6th editionIsrael Regardie with The Vision and the Voice (Liber CCCCXVIII, XXX Aerum vel Saeculi)Aleister Crowley