English
subexcedant
From sub- + exceed + -ant.
Today it means
adj (of a sequence of nonnegative integers) such that the value of each term is less than the position of that term in the sequence (e.g. the first term is less than 1, the second term is less than 2, etc.)
Language periods are conventional ranges, not dates for this word.
Etymograph / subexcedant