from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An essential element or condition: "The perfect cake is the sine qua non of the carefully planned modern wedding” ( J.M. Hilary).
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An essential or indispensable element, condition, or ingredient.
from The Century Dictionary and Cyclopedia
- n. Something absolutely necessary or indispensable; an indispensable condition: as, he made the presence of a witness a sine qua non; used attributively, indispensable; necessary.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a prerequisite
Late Latin sine quā (causā) nōn, without which (cause) not : Latin sine, without + Latin quā : ablative of quī, which, what, who + Latin nōn, not.(American Heritage® Dictionary of the English Language, Fourth Edition)
Latin sine qua non, “without which [cause] not” (Wiktionary)