Short definition

A brief support — a sentence, a quotation, a formula — that carries a pillar of thought and serves to hold it in active memory rather than to retrieve it. Entry is decided by personal resonance, and the deck is deliberately small.

Synonyms and variants

Card, anchoring card, memory card. The plural "the deck" refers to the active set.

"Pillar card" is the variant used when the emphasis falls on what the card anchors rather than on the gesture of review; it is the same object.

Not to be confused with

• Pillar of thought — the conviction itself, independently of the support that carries it. The card is the object, the pillar is the content.
• Atomic note — a self-contained, conceptual and reusable note, with a single center of gravity, meant to be linked to others and retrieved on request; it can be numerous, the card has to be rare.
• Mnemonic review card — a question/answer card carrying objective content, whose success is measured by exact recall.

Examples

A quotation read in a book, copied out by hand because on reading it you recognized something you already thought without having put it into words, then reread every two weeks and confronted with the situations experienced in between.

Ambiguities / debates

The schoolroom use of the word remains dominant, and it pulls toward memorizing objective content. The use retained here keeps the form — brevity, handling, spaced review — and changes the entry criterion: personal resonance instead of exam usefulness.