What are suit lapels?

 Basic lapel guide:
There are three main types of lapel.

The notch

The peak

and the shawl

Notch lapels are most common and are de facto style for classic business wear. Peak lapels are traditional on double breasted jackets and should be mixed with your casual jackets regularly. The shawl lapel is rare and mostly seen, when used, on DJ's (tuxedos for my American readers).