# Beamer, description, and space for labels

When using

\begin{description}[abc]
\item[ab] Some description
\item[abc] Some description
\item[abcd] Some description
\end{description}


Space of length "abc" is reserved for labels. So "ab" will be right aligned, while "abcd" will be longer than the indentation of wrapped lines.

When using beamer, I use

\begin{description}[<+->]
\item[ab] Some description
\item[abc] Some description
\item[abcd] Some description
\end{description}


to specify that the items should appear one after the other. Is there any way to specify how much space should be reserved for labels while doing this?

just put the spec after [<+->]:

\documentclass{beamer}
\begin{document}
\begin{frame}
\begin{description}[<+->][abc]
\item[ab] Some description
\item[abc] Some description
\item[abcd] Some description
\end{description}

\begin{description}[abc]
\item[ab] Some description
\item[abc] Some description
\item[abcd] Some description
\end{description}
\end{frame}
\end{document}


The result is the same.

You could use \phantom statements in the first two \items. That way, all labels will have the same width and alignment properties.

\documentclass{beamer}
\begin{document}
\begin{frame}
\begin{description}[<+->]
\item[ab\phantom{cd}] Some description
\item[abc\phantom{d}] Some description
\item[abcd] Some description
\end{description}
\end{frame}
\end{document}