\begin{definition}[Definition:Floor Function/Notation]
Before around $1970$, the usual symbol for the '''floor function''' was $\sqbrk x$.
The notation $\floor x$ for the '''floor function''' is a relatively recent development.
Compare the notation for the corresponding ceiling function, $\ceiling x$, which in the context of discrete mathematics is used almost as much.
Some sources use $\map {\mathrm {fl} } x$ for the '''floor function''' of $x$. However, this notation is clumsy, and will not be used on {{ProofWiki}}.
\end{definition}