antepenultimate

antepenultimate \an-tee-pi-NUHL-tuh-mit\, adjective:

1. Third from the end.
2. Of or pertaining to an antepenult.

noun:
1. An antepenult.

The vengeful eagles of the open sequence [and] the birds of augury watched outside the library and the emblematic kinsmen who shake 'the wings of their exultant and terrible youth' in the antepenultimate entry in Stephen's diary.
-- James Joyce, introduction by Hugh Kenner, Ulysses

But all day that is how it is, from the first tick to the last tack, or rather from the third to the antepenultimate, allowing for the time it needs, the tamtam within, to drum you back into the dream and drum you back out again.
-- Samuel Beckett, Mercier and Camier

This adjective is the product of three Latin roots: ante meaning "before," paen meaning "almost" and ultima meaning "last."