A term applying to firearms, meaning that the clip is located behind the trigger.
The Steyr Aug uses a bullpup design
Bullpup refers to a fiream that has it's action and magazine located behind the trigger group. This design allows for a shorter overall design in relation to barrel length and an increase in maneuverability.
Rifles such as the FN F2000, IMI Tavor, and the GIAT FAMAS all utilize a bullpup design.