The Precise Word
They say the average mass-market novel is written at a sixth grade reading level. Now, that terminology is nebulous, at best, because if you talk about a sixth grade education in say, 1780, versus a sixth grade education now, the words you'd find in the vocabulary of students sampled from each era would be vastly different. I'm going to assume when the statistics people say "6th grade education," they mean a relatively contemporary version of that body of knowledge.