# Make font size smaller in remark systematically

My LaTeX begins with \documentclass[9pt,a4paper,reqno]{amsbook}. I want the font size of "Remark" even smaller, is there a way to do this systematically? (But the other parts keep unchanged.)

And maybe better with different font (most part it looks like Times New Roman, and in Theorem environment it's italian, I want the font in "Remark" to be more different).

My "Remark" is defined like this:

\theoremstyle{plain}
\newtheorem{thm}{Theorem}[section]
\newtheorem{remark}[thm]{Remark}


The trick is to initiate \small before the remark, which needs to ensure the previous paragraphs has ended.

\documentclass{article}
\usepackage{amsthm}

\usepackage{lipsum}

\theoremstyle{plain}
\newtheorem{thm}{Theorem}[section]

\theoremstyle{definition}
\newtheorem{zremark}[thm]{Remark}

\newenvironment{remark}{\par\small\zremark}{\endzremark}

\begin{document}

\lipsum*[3]

\begin{thm}
\lipsum[1][1-2]
\end{thm}

\lipsum[2][1-3]

\begin{remark}
\lipsum[3][1]
\end{remark}

\lipsum[4]

\end{document}


If you want to change the font family in remarks, the simplest way is to define a new theorem style.

\documentclass{article}
\usepackage{amsthm}

\usepackage{lipsum}

\newtheoremstyle{myremark}% name of the style to be used
{\topsep}% measure of space to leave above the theorem. E.g.: 3pt
{\topsep}% measure of space to leave below the theorem. E.g.: 3pt
{\sffamily\upshape}% name of font to use in the body of the theorem
{0pt}% measure of space to indent
{.}% punctuation between head and body
{ }% space after theorem head; " " = normal interword space
{}% standard setting

\theoremstyle{plain}
\newtheorem{thm}{Theorem}[section]

\theoremstyle{myremark}
\newtheorem{remark}[thm]{Remark}

\begin{document}

\lipsum*[3]

\begin{thm}
\lipsum[1][1-2]
\end{thm}

\lipsum[2][1-3]

\begin{remark}
\lipsum[3][1]
\end{remark}

\lipsum[4]

\end{document}


• Thanks, I tryed and it works! Do you know how to make it like the font style \texttt, like here: tex.stackexchange.com/questions/134056/…. My goal is to distinguish it from the around text. So better not change font size but the style (as the font size is already very small for the whole text, \small is not very signaficant). Jan 8 '19 at 8:55
• @Lao-tzu Use \sffamily instead of \small (I wouldn't use a monospaced font). Jan 8 '19 at 9:01
• I try \sffamily, but it looks no effect (still the same font as the picture in your answer). Jan 8 '19 at 9:04
• @Lao-tzu I added a different way. Jan 8 '19 at 9:50