existentia

Existentia in medieval Latin comes from existere — to step forth, to emerge, to stand out. The prefix ex- (out) combined with sistere (to stand, to place). In scholastic philosophy, existentia was the technical counterpart to essentia (essence). Thomas Aquinas and his followers debated whether a thing's existence was distinct from its essence. The word was dry, academic, and nobody outside a university cared about it.

Soren Kierkegaard changed that. Writing in Danish in the 1840s, he argued that philosophy had become obsessed with abstract systems — Hegel's in particular — and had forgotten the existing individual. Kierkegaard did not use 'existential' as a label for his work, but his emphasis on subjective experience, anxiety, and personal choice became the foundation for what the twentieth century would call existentialism.

Jean-Paul Sartre made the word famous after 1945. His lecture 'Existentialism Is a Humanism' turned a philosophical position into a cultural movement. 'Existence precedes essence' — you exist first, and define yourself through choices afterward. Simone de Beauvoir, Albert Camus, and Martin Heidegger (who rejected the label) all got swept into the category. The word moved from lecture halls to Left Bank cafes to newspaper headlines.

By the 1960s, 'existential' had become an all-purpose adjective for anything involving deep uncertainty or dread. An existential crisis. An existential threat. The medieval Latin word for 'pertaining to existence' now means 'so serious it threatens your sense of self.' The scholastics would not recognize it.