Illustrated Glossary of Organic Chemistry

Stereocenter (chiral center): An atom with three or more substituents, interchanging of two of these substituents leads to another stereoisomer. Most commonly, a carbon atom bearing four different substituents.

sp3 carbon stereocenters
sp2 carbon stereocenters
Sulfur and nitrogen stereocenters

 
 
  
Stereocenters at sp3 carbon
Stereocenters at sp2 carbon
Sulfur and nitrogen stereocenters