diff --git a/preamble.tex b/preamble.tex
index 5b5bd8df6..014803cf7 100644
--- a/preamble.tex
+++ b/preamble.tex
@@ -137,20 +137,7 @@
 
 \newcommand{\bibitemtitle}[1]{\emph{#1}}
 
-% henrikt-ma: Introducing semantic macro for 7 definitions spread out over two chapters
-% that for unclear reasons use their own style, including numbering.  Sorting out if numbered
-% definitions should be used more or not at all is part of issue #2570.
-%
-% Definitions are numbered, but are not suitable for use with \autoref, as \autoref is not aware
-% of our custom definitions.  (They say there are better alternatives to \autoref, more suited
-% for this kind of customization...)  To avoid accidental use of \autoref, a definition should
-% also avoid use of \doublelabel, and instead use \definitionlabel.  Instead of \autoref, the definition
-% should be referenced using \definitionref
-%
-% If we'd like to have definitions spanning over several paragraphs, we should use an environment
-% instead of a command, but then we also need to find a way to visualize where the definition ends;
-% alternatives that come to mind include boxes, indentation, a right-flushed black square, but the
-% big challenge would be to find something that also works well with LaTeXML.
+% Environment for definitions.
 \usepackage{amsthm}
 \newtheoremstyle{mlsdefinition}
   {\topsep}   % ABOVESPACE
@@ -162,8 +149,13 @@
   {.75em}     % HEADSPACE
   {Definition~#2. \firstuse{#3}}        % CUSTOM-HEAD-SPEC
 \theoremstyle{mlsdefinition}
-\newtheorem{definition}{Definition}[chapter]
-\newcommand{\definitionautorefname}{definition}
+% In order to show where the definition ends, we put a \qed at the end.  This can't be done using \newtheoremstyle,
+% so instead we make the 'definition' environment a wrapper around the amsthm-base environment.
+\makeatletter
+\newtheorem{definition@inner}{Definition}[chapter]
+\newcommand{\definition@innerautorefname}{definition}
+\newenvironment{definition}{\begin{definition@inner}}{\qed\end{definition@inner}}
+\makeatother
 
 \setcounter{secnumdepth}{5}
 % Note: Toc changed for appendex