Definition of "contrastive"

This thesis is an attempt to apply the theory of transformational grammar to the Japanese language. […] Comparison of the structure of Japanese and English is also our concern, whenever possible, and it is seen that the transformational theory is helpful in such contrastive studies.

1965 June 4, Shigeyuki Kuroda, “Generative grammatical studies in the Japanese language”, in DSpace@MIT‎, retrieved 2014-02-24

Consider the first, allegedly contrastive fact, that there were some bank robbings by Sutton rather than no robbings at all by Sutton.

1985, David-Hillel Ruben, The Metaphysics of the Social World, page 141

Vowel length is contrastive.

2008, Alexandra Aikhenvald, The Manambu Language of East Sepik, Papua New Guinea, page 1