  We present a new efficient method for approximate search in electronic
lexica. Given an input string (the pattern) and a similarity threshold, the
algorithm retrieves all entries of the lexicon that are sufficiently similar to
the pattern. Search is organized in subsearches that always start with an exact
partial match where a substring of the input pattern is aligned with a
substring of a lexicon word. Afterwards this partial match is extended stepwise
to larger substrings. For aligning further parts of the pattern with
corresponding parts of lexicon entries, more errors are tolerated at each
subsequent step. For supporting this alignment order, which may start at any
part of the pattern, the lexicon is represented as a structure that enables
immediate access to any substring of a lexicon word and permits the extension
of such substrings in both directions. Experimental evaluations of the
approximate search procedure are given that show significant efficiency
improvements compared to existing techniques. Since the technique can be used
for large error bounds it offers interesting possibilities for approximate
search in special collections of "long" strings, such as phrases, sentences, or
book ti
