% This file is public domain
 % If you want to use arara, you need the following directives:
 % arara: pdflatex: { synctex: on }
 % arara: makeglossaries
 % arara: pdflatex: { synctex: on }
\documentclass{article}

\usepackage[colorlinks,plainpages=false]{hyperref}
\usepackage[nonumberlist]{glossaries}

\newglossary[nlg]{symbols}{not}{ntn}{Symbols}

\makeglossaries

\loadglsentries{database1}
\loadglsentries[symbols]{database2}

\begin{document}

\glsaddall

\printglossaries

\end{document}