Sine qua non By Deane Barker • November 12, 2021 • Latin for “without which, not.” It’s used to refer to something indispensable – “without this thing, this other thing is not possible.” Why I Looked It Up I can’t remember the specific usage that caused me to look it up, but I’ve seen this for years. Postscript Added on July 1, 2023 From The Tyranny of Clichés: …an idea that assumes with Hegelian orthodoxy that expansions of the State are the sine qua non of progress. Postscript Added on October 20, 2023 From Harry Potter and the Art of Spying: What is sine qua non? A wonderful Latin phrase that means an essential action, condition, or ingredient; as a legal term, it means a condition or preexisting ingredient without which that which follows cannot exist.