Hello!
A biconditional statement is when one conditional statement and it's converse is true.
A conditional statement is an "If <em>hypothesis</em>, then <em>conclusion</em>" statement.
A converse statement is an "If <em>conclusion</em>, then <em>hypothesis</em>" statement.
Looking at this, both of these statements have their hypothesis and conclusion switched.
Thus, a biconditional statement is a "<em>Hypothesis</em> IFF <em>conclusion</em>." In this statement, IFF means if and only if.
Therefore, when IFF is used in a biconditional statement, it means if and only if.
