# Deactivating italic text in body of a “definition” environment [duplicate]

I definied a new theorem via

\newtheorem{def}{definition}


But the text has a italic font and i do not want that. how can i deactivate the italic font?

• What package are you using to create your theorems? – Werner Nov 22 '16 at 16:47
• Aside: LaTeX won't let you set up an environment called def. You'll get an error message such as ! LaTeX Error: Command \def already defined.. Use defn or something else instead. – Mico Nov 22 '16 at 16:51
• potential duplicate: Non italic text in theorems, definitions, examples – barbara beeton Nov 22 '16 at 16:55

I assume you're using a theorem-related package such as amsthm. If that's the case, just issue the instruction

\theoremstyle{definition}


\newtheorem{defn}{Definition}


A full MWE:

\documentclass{article}
\usepackage{amsthm,lipsum}
\theoremstyle{definition}
\newtheorem{defn}{Definition}
\begin{document}
\begin{defn}[Lipsum]
\lipsum*[2] % filler text
\end{defn}
\end{document}

• If you use the ntheorem package rather than the amsthm package to set up theorem-like environments, you should replace \theoremstyle{definition} with \theorembodyfont{\upshape}. – Mico Nov 22 '16 at 16:56