Breaking line in shadow box

Question

I am going to write Definitions: Least element, Greatest element, minimal element, maximal element in a shadow box but the line exceeds the page margin. Here's my code:

\documentclass[12pt,a4paper]{article}    
\usepackage{amsmath}  
\usepackage{amsthm}  
\usepackage{amssymb}  
\usepackage[utf8x]{inputenc}  
\usepackage{centernot}  
\usepackage{fancybox}   
\usepackage[breakable]{tcolorbox}  
\usepackage{tabularx}  
\usepackage{graphicx}  
\usepackage{parskip}  
\DeclareUnicodeCharacter{2061}{}   
\DeclareUnicodeCharacter{8289}{}  
\begin{document}  
       text  
\par 
\shadowbox{\textbf{Definitions: Upper bound, Least Upper Bound, Lower Bound, Greatest Lower Bound}}  
\par \hspace{0.3cm}  
  text  
\end{document}

How do I break the long line within shadow box?

Answer 1

As explained in the fancybox documentation (page 5):

Entire paragraphs or other vertical mode material such as displayed equations can be nested in a \parbox or minipage.

MWE

\documentclass{article}    
\usepackage{fancybox}   

\begin{document}  

 \shadowbox{%
   \parbox{\textwidth}{%
     \bfseries
      Definitions: Upper bound, Least Upper Bound, Lower Bound, Greatest Lower Bound}}

 \shadowbox{%
    \parbox{\textwidth}{%
        \bfseries
        Definitions: Upper bound, Least Upper Bound,\par Lower Bound, Greatest Lower Bound}}

\end{document}