memor

The root memor comes from Latin, where two closely linked words sit at its heart.

memor was an adjective meaning "mindful, remembering" — describing a person who keeps something in mind and does not let it slip away. From it Latin built the noun memoria, "memory" — both the faculty of remembering and the act of holding the past in mind.

These two ideas — the power to remember and the act of keeping in mind — branch into the whole English family:

- memory is the faculty itself: the storehouse where the past is kept. (English later borrowed the same word for computer storage — a machine's "memory.")
- memorize / memorise (-ize/-ise, "to make") = to actively put something into your memory, to commit it to heart. (The -ize spelling is American; -ise is the British variant.)
- memorable (-able, "worthy of") = worth remembering, the kind of thing memory naturally holds onto.

From memoria came a cluster of words about written reminders — things that exist precisely because human memory fails:

- memorandum is Latin for "a thing to be remembered" (the gerundive of memorare) — a note written so it won't be forgotten.
- memo is just the everyday clipping of memorandum.
- memoir travelled through French (mémoire) and means a personal record of things remembered — a written-down memory of one's own life.

A second cluster is about honouring memory in public:

- memorial (-al, "relating to") = something that keeps a person or event in collective memory — a monument, a ceremony, a day set aside.
- commemorate (com- "together" + memor) = to remember together, as a community — to mark an anniversary or honour the dead with a shared act.
- memento comes straight from the Latin imperative "remember!" — so a memento is literally a "remember!" object, a keepsake that tells you not to forget.

Two members reshape the meaning with prefixes:

- immemorial = im- ("not") + memorial: so far back that it lies beyond memory — "from time immemorial" means older than anyone can recall.
- remember took a different road: Latin re- ("again") + memorari gave rememorari, "to bring back to mind," which through Old French became remembren. To remember is to make yourself mindful again of something you once knew.

The pattern across the family is simple: memor is always about the line between what stays in mind and what slips away — and most of these words exist because we are afraid of forgetting.