>> I've come a cross a passage in a novel to be translated, describing a
>> batch of hand-adressed envelopes. the sentence "excelsior, 500 count"
>> is included in the line with no explanation.
I would vote for Excelsior being the name of a particular size or style of
envelope. If the orginal poster on this is still around perhaps they could
give us a little mmore context. Title and author? When and where published?