A zeppelin is a rigid airship manufactured by a particular company [...] A blimp (technically called a “pressure airship”) is a powered, steerable, lighter-than-air vehicle whose shape is maintained by the pressure of the gases within its envelope. A blimp has no rigid internal structure; if a blimp deflates, it loses its shape.
http://www.airships.net/dirigible
A zeppelin is a rigid airship manufactured by a particular company [...] A blimp (technically called a “pressure airship”) is a powered, steerable, lighter-than-air vehicle whose shape is maintained by the pressure of the gases within its envelope. A blimp has no rigid internal structure; if a blimp deflates, it loses its shape.