↔
Symbol  Format  Data 

↔  Code Point 
U+2194 
TeX 
\leftrightarrow 

SVG 
This symbol is used to indicate that two statements are logically equivalent, meaning that they are both true or both false. It signifies a biconditional relationship, so if one statement is true, then the other must also be true, and vice versa. For example:
A quadrilateral is a square ↔ It has four equal sides and four right angles.
Long left right arrow symbol.
The symbol of an arrow pointing to the left.
The symbol of an arrow pointing to the right.