propenultimate

Etymology
From

Adjective

 * : two places before last.
 * 1) * 1929, Martin Armstrong, The Sleeping Fury, book 1 Charlotte At Fifty, chapter 1:
 * “Halnaker is the family name?” “Yes. Spelt H-a-l-n-a-k-e-r and pronounced Hannaker, with the accent on the Hann—the pro-penultimate, as we were taught to call it at school. The propenultimate, if you please. What unmitigated nonsense! Why not the last-but-two?”