List of symbols, taken from http://filer.case.edu/oxb6/listofsymbols.html for ease of use with Gists

listOfSymbols.tex

%% Your packages

\usepackage{array} %for vertical thick lines in tables
\usepackage{multirow} %multirow tables 
\usepackage{nicefrac} %for fractions like 1/4
%Package list ends here

% Macro for 'List of Symbols', 'List of Notations' etc...
\def\listofsymbols{\input{symbols} \clearpage}
\def\addsymbol #1: #2#3{$#1$ \> \parbox{5in}{#2 \dotfill \pageref{#3}}\\} 
\def\newnot#1{\label{#1}}

%% ...

\tableofcontents
\listoftables \addcontentsline{toc}{chapter}{List of Tables}
\listoffigures\addcontentsline{toc}{chapter}{List of Figures}
\newpage
\chapter*{List of Symbols\hfill} \addcontentsline{toc}{chapter}{List of Symbols}
\listofsymbols

%% ...
Here, if the dimensions of A \newnot{symbol:A}, B \newnot{symbol:B}, and C \newnot{symbol:C} are nxn, nxm and lxn \newnot{symbol:nml} respectively; then n-vector x\newnot{symbol:x} denotes the system state; m-vector u denotes system control; and the l-vector y denotes the system output.

symbols.tex

%%%%%%%%%%%%%%%%%%%%%%%
%Sample List of Symbols
%%%%%%%%%%%%%%%%%%%%%%%
\begin{tabbing}
% YOU NEED TO ADD THE FIRST ONE MANUALLY TO ADJUST THE TABBING AND SPACES
$n$~~~~~\=\parbox{5in}{Vector size\dotfill \pageref{symbol:nml}}\\
%ADD THE REST OF SYMBOLS WITH THE HELP OF MACRO
\addsymbol m: {Vector size}{symbol:nml}
\addsymbol l: {Vector size}{symbol:nml}
\addsymbol x: {State vector}{symbol:x}
\addsymbol u: {Control input}{symbol:x}
\addsymbol y: {Output vector}{symbol:x}
% .
% .
% .
\addsymbol \mathbf{A}: {State Matrix}{symbol:A}
\addsymbol \mathbf{B}: {Input Matrix}{symbol:B}
\addsymbol \mathbf{C}: {Output Matrix}{symbol:C}
% .
% .
% .
% ALWAYS KEEP THE FOLLOWING LINE
\end{tabbing}