Plural of familiar: close friends or associates, or in historical contexts, spirits or demons believed to serve witches.
From Latin familiaris (of the household, domestic). In medieval and early modern usage, familiar spirits were supernatural servants bound to witches—a fascinating shift from 'household member' to 'supernatural servant.'
The familiar spirit mythology reveals how people once explained the sensation of 'intrusive thoughts'—voices in your head that felt separate from yourself. Modern psychology shows these are just your own brain, but the familiar spirit idea shows humans trying to make sense of their own minds.
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