sine qua non
LOCUCIÓN LATINA
Conditio sine qua non; Condición sine qua non; Condicio sine qua non; Condicion sine qua non
= sine qua non
Ex: Unfortunately, continuing the assignment of Library of Congress subject headings -a sine qua non, according to the views of the American librarian community- would have meant an increase in operating costs of approximately $1,000,000 per annum.