Body Types

Humans have 3 basic body types:

Borrowed from pinterest.com

These also exist in combinations such as EctoMesomorph, EndoMesomorph, etc.  Most people, including myself, have traits from 2 different types.

Borrowed from wiseandfit.com

These vary quite a bit and are independent of weight and height.  For example, someone with an ectomorph body type that is 6' 5" and 250 is going to be stronger than a mesomorph that is 5' 6" and 140.

Ectomorph

This is my body type.  This body type is a smaller frame than the mesomorph and has a harder time gaining muscle.  These are your "hardgainers" and long distance runners.  Fortunately, I also posses attributes of the mesomorph.  I know this because I was able to do sprints and jumps for track and field and I enjoy weightlifting.
Encyclopedia Definition

Mesomorph

Characteristically strong, these individuals are meant for heavy lifting.  Their bodies are thicker and have denser musculature.  They usually carry less body fat and can strengthen and grow muscle easily.

Encyclopedia Definition

Endomorph

These are your football linemen, strongmen, sumo wrestlers etc.  This body type puts on fat very easily while also gaining muscle easily.  As the picture shows, they may have large amounts of muscle but have a harder time showing it than the other two classifications.

Encyclopedia Definition

Borrowed from pinterest.com