% LEXIKON.STY
\RequirePackage{ifthen}

\newboolean{first}
\newcommand{\lastchar}{}
\newcommand{\ps@lexikon}
{\renewcommand{\@oddhead}
  {\hfil\textbf{\Large\botmark}%
  \hspace{1cm}\arabic{page}}
\renewcommand{\@evenhead}
  {\arabic{page}\hspace{1cm}%
  \textbf{\Large\botmark}\hfil}
\renewcommand{\@evenfoot}{}
\renewcommand{\@oddfoot}{}
}

\newenvironment{lexikon}
{\setboolean{first}{true}
 \renewcommand{\lastchar}{}
 \newpage\twocolumn
 \let\@oddh\@oddhead  \let\@evnh\@evenhead
 \let\@oddf\@oddfoot  \let\@evnf\@evenfoot
 \pagestyle{lexikon}
}
{\end{description}
 \onecolumn
 \let\@oddhead\@oddh  \let\@evenhead\@evnh
 \let\@oddfoot\@oddf  \let\@evenfoot\@evnf
 \markboth{}{}
}

\def\entry[#1#2]
{\ifthenelse{\equal{\lastchar}{#1}}
  {}
  {\ifthenelse{\boolean{first}}
    {\setboolean{first}{false}}
    {\end{description}}
   \renewcommand{\lastchar}{#1}
   \medskip
   \noindent\textbf{\Huge #1}
   \rule{0.9\columnwidth}{2mm}
   \begin{description}
  }
 \item[#1#2]\mark{#1#2}
}