LaTeX:
<small><pre>
\documentclass{article}
\begin{document}
\end{description}
\end{document}
</pre></small>
ConTeXt: <tt>\setupdescription</tt> with some special parameters
<tt>margin=</tt><i>indentation</i>)
<small><pre>
\definedescription[notation][
headstyle=bold,style=normal, align=left, location=hanging, width=broad, margin=1cm, ]
\starttext
\notation{A very very very very long item}
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
\notation{i}
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
\stoptext</pre></small>
The empty lines (or <tt>\par</tt>) after each description
<b>Hint:</b> This solution uses the <tt>distance=</tt><i>dimension</i>
distance for separation of label and text. I could not find a solutionyet, which aligns the text in the first line with that of the otherlines, if the label is short enough.