Definition of Z-grade

The term Z movie (or grade-Z movie) arose in the mid-1960s as an informal description of certain unequivocally non-A films. It was soon adopted to characterize low-budget pictures with quality standards well below those of most B movies and even so-called C movies. While B movies may have mediocre scripts and actors who are relatively unknown or past their prime, they are for the most part competently lit, shot, and edited. The economizing shortcuts of films identified as C movies tend to be evident throughout; nonetheless, films to which the C label is applied are generally the products of relatively stable entities within the commercial film industry and thus still adhere to certain production norms.