Apologies once again for the lack of wordiness from me of late. I've been ill with a horrible cough (similar to whooping cough, only without the whoop!). I'm almost all better now, and more than able to post awesome words. For example:
That precedes or stands immediately before the antepenult; the last but three.
From Latin antepaenultima the second (syllable) from the last, fem. of antepaenultimus standing before the penult.
1852 Dana Crust. ii. 1061:The præantepenult [joint] has the anterior seta as long as the joint.
In a rare case where the use of more words is considered less confusing than the one, the list of ways to describe something as 'the fourth from last' definitely includes this word somewhat behind the preantepenult!