The type of door in your photograph is called a "six-panel door". The design is today something of an anachronism, but originally the panels would be separate pieces of wood set within a robust "lattice" of wood frame members.

This design allowed each of the structural elements to expand and contract independently in response to changing temperature and humidity, which helped prevent the door from warping, and ensured a better seal around the door-frame.

Today most six-panel style doors used in residential construction are made out of an aluminum shell filled with insulation, making the six-panel door an example of skeuomorphic design.