1920s; earliest use found in Proceedings of the National Academy of Sciences of the United States of America. From non- + trivially, after non-trivial.
Definition of non-trivially in US English:
non-trivially
adverbnɒnˈtrɪvɪəli
In a non-trivial manner.
Origin
1920s; earliest use found in Proceedings of the National Academy of Sciences of the United States of America. From non- + trivially, after non-trivial.