- Penultimate means last but one, but that's last in the sense of the one before the final one, not the one before the previous one. ...
- penultimate should work, assuming the current item is the latest item, and we are interested in the one before it.
What do you call year before previous year?
Year before last designates a specific year. If you say I finished school the year before last we understand that you finished school during the year which preceded last year: sometime in 2013. Before last year designates an indefinite timespan which ended at the beginning of last year.
What do you call the one before the last one?
Another option is 'last but one' (for penultimate), and 'last but two' (for antepenultimate).
