# Nomenclature and line breaks

I'm trying to format the nomenclature such that there is, ideally, a curly bracket around a series of items with 1 definition. If that's not possible then at least having a line break in between successive items then having the definition in the middle would be great.

(I've read the documentation and it says that You can have have line breaks in the argument' but I have been unsuccessful at implementing it).

I've included a relatively short working code showing what I would ideally like in the nomenclature.

\documentclass{report}

\usepackage{amsmath}
\usepackage{nomencl}
\makenomenclature

\begin{document}

\printnomenclature

\begin{equation*}
\left[K\right]=
\begin{pmatrix}
K_{xx}  &   K_{xy}      \\
K_{yx}  &   K_{yy}      \\
\end{pmatrix}
\nomenclature{$K$, $K_x$, $K_y$, $K_{xx}$, $K_{yy}$, $K_{xy}$, $K_{yx}$}{Permeability values {$[m^2]$}}%
\end{equation*}

\left. \begin{aligned} &K, \\ &K_x,~K_y, \\ &K_{xx},~K_{yy}, \\ &K_{xy},~ \&~K_{yx} \end{aligned} \right\}Permeability values {$[m^2]$}

\end{document}

-

So I have a workaround appended. Essentially adding either \begin{aligned} and \end{aligned} allows you to add line breaks. For what I was looking to do I found an rrcases command which makes it look nice.

 %Nomenclature curly braces
\makeatletter
\newenvironment{rrcases}{%
\matrix@check\rrcases\env@rrcases
}{%
\endarray\right\rbrace%
}
\def\env@rrcases{%
\let\@ifnextchar\new@ifnextchar
\left.
\def\arraystretch{1.7}%
\array{@{}l@{~}l@{}}%
}
\makeatother

\nomenclature{$\begin{rrcases}K\\K_x\\K_y\\K_{xx}\\K_{yy}\\K_{xy}\\K_{yx}\end{rrcases}$}{Permeability values\nomunit{m^2}}%
`
-