# [Tex/LaTex] How to get non-italic words in a theorem environment

theorems

I want some words in my theorem environment to not be italic. I know there are simple ways to get the entire theorem in roman, but I'm looking for an italic theorem with specified words in roman.

I tried:

\documentclass{article}
\usepackage{framed}
\usepackage{amsthm}
\usepackage[svgnames]{xcolor}

\newtheorem{mydef}{Definitie}[section]

\begin{document}
I want \textrm{this} word to be non-italic.

But apparently \textrm is not the way to go because everything is still italic
I want \textup{this} word to be non-italic.