\begin{definition}[Definition:Definition/If or Iff]
It is a standard convention, when making a definition in mathematics, to use '''if''' to introduce the definiens, when in fact the intent is generally '''iff''', that is: '''{{iff}}'''.
This convention is specifically '''not followed''' on {{ProofWiki}}, where the mandatory style is to use '''{{iff}}'''.
\end{definition}