Pillar-boxes?? Haven't heard anything like that referred to for years and years!
Letter boxes, and "LetterBox" format
Well, technically, "post box" i guess since you don't just put letters in the post box. Sigh.
Anyway, i thought widescreen on a 4:3 with bars top and bottom was letterbox? (Not that i've read the entire thread, and that could already have been said!)