In both Unicode 1.0 and Unicode 2.0 ­ is called "soft hyphen"
or "discretionary hyphen", so it is available, but perhaps not reliably
supported by 8859-1 applications.
Also available is the zero-width
space ​ which can be used to provide non-hyphenating line-break
points inside long technical terms (this might be useful in chemical names,
where a dash of any kind might be misleading) and in languages in which
words are not delimited by spaces.
For example, supercali​fragalistic&x200B;expialladocious.
Rick Jelliffe