SINE QUA NON Meaning of SINE QUA NON in English [ ˌsɪni kwα:'nəʊn , ˌsɪni kweɪ 'nɒn ]■ noun a thing that is absolutely essential.OriginL., lit. '(cause) without which not'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004