You can also use eqlist
or desclist
:

\documentclass{article}
\usepackage{eqlist} % <-- for solution 1
\usepackage{desclist} % <-- for solution 2
\usepackage{geometry,parskip,lipsum} % irrelevants for the question
\begin{document}
\lipsum[3][1-7] % Only dummy text
% Solution 1
\begin{eqlist} % optionally [\setlength\labelsep{...}]
\item[\bfseries Canonical Ensemble:] System with fixed particle number, volume and temperature.\\ (Microcanonical ensemble has fixed energy instead of temperature!)
\item[\bfseries Ensemble Telúrico:] Supposed musical group of the comedy-musical group Les Luthiers that interpret the music of the supposed composer Johann Sebastian Mastropiero.
\end{eqlist}
\lipsum[3][1-7] % More dummy text
% Solution 2
\begin{desclist}{\hskip14em}{:\qquad}[\bfseries Canonical Ensemble]
\item[\bfseries Canonical Ensemble] System with fixed particle number, volume and temperature.\\ (Microcanonical ensemble has fixed energy instead of temperature!)
\item[\bfseries Ensemble Telúrico] Supposed musical group of the comedy-musical group Les Luthiers that interpret the music of the supposed composer Johann Sebastian Mastropiero.
\end{desclist}
\lipsum[3][1-7] % Dummy text again
\end{document}
Similarly with \usepackage{expdlist}
you can use the same items of "Solution 1" but in a extended description
list that allow options, in this way:
\begin{description}[\setlabelphantom{Canonical Ensemble:}]
\item ...
\end{description}
Or you can use use tabto,
making a \hangindent
as long as the \tab
:
\documentclass{article}
\usepackage{tabto,parskip}
\TabPositions{14em,16em}
\begin{document}
{\bfseries Canonical Ensemble:} \tab\hangindent14em System with fixed
particle number, volume and temperature.\\ (Microcanonical ensemble
has fixed energy instead of temperature!)
{\bfseries Ensemble Telúrico:}\tab\hangindent14em Supposed musical
group of the comedy-musical group Les Luthiers that interpret the
music of the supposed composer Johann Sebastian Mastropiero.
Although the output is apparently similar, in this case is not at all equivalent to a list, so in many different situations your mileage will vary with one or another type of solutions.