The Oxford Thesaurus An A-Z Dictionary of Synonyms - shorten v.

1) cut, curtail, cut off or down or short, reduce, diminish, trim; lop off, dock, prune; hem: Please shorten the time you spend in the bathroom in the mornings. This skirt has already been shortened. 2) condense, abridge, abbreviate, digest, compress: Can one shorten the book without losing too much of the characterization?