Laugh? I Nearly Paid My Licence Fee
Film, Media & TV1 min ago
No best answer has yet been selected by koster. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.Interesting question, and answer from QM. Another way of looking at it might be that years ago, when it was common for cinemas to show more than one feature, plus cartoons, trailers were run between the items. So (if my memory serves me correctly) trailers were actually shown both before and after a film.
If this is correct, then 'trailer', meaning coming after would make sense, and it was in those days that the word first gained currency so that would fit.