Well, there are reasons why there are dictionaries and ethimology dictionaries: http://www.thefreedictionary.com/trivial http://www.thefreedictionary.com/trivia

Well, there are reasons why there are dictionaries and ethimology dictionaries: http://www.thefreedictionary.com/trivial http://www.thefreedictionary.com/trivial http://www.etymonline.com/index.php?term=trivial http://www.etymonline.com/index.php?term=trivial it has usually two slightly different meanings, adopted more or less at the same time at the end of the 16th century in English. The actual meaning is not (in this context) "unimportant" and not exactly "easy", but rather - as I see it slightly different - "simple" in the sense of "commonplace" or rather "at the reach of the ordinary people". As well, non-trivial does not IMHO really mean "complex" but rather "beyond the reach of the ordinary people" or "needing some non-common reasoning or tools/methods to be reached", it is almost the same, but not exactly the same.