What are the meanings of dotted and wavy lines in structural formulas?
I was wondering what the wavy and the dotted line represent?



A dashed line indicates that the bond is extending behind the plane of the drawing surface
A bold-wedged line indicates that the bond is protruding out from the plane of the drawing surface
A solid line indicates that the bond exists in the plane of the drawing surface.
A wavy line indicates that the stereochemistry of the bond is unknown.
A dotted line indicates that the bond is not a full bond, it is only a partial bond as in a hydrogen bond or a partially formed or broken bond in a transition state. Also, as Mrigank Pawagi notes in the comments, the dotted line can be used along with the solid line to denote bonds that have partial double bond character due to resonance.
An arrow indicates a dative bond in which both electrons in the bond originate from one atom (not common)