A sturdy military fortification, often of concrete, with gunports.
A reinforced building from which to control hazardous operations, such as an explosion or a rocket launch.
A temporary fortification built by troops in the field; a defensive earthwork in the field.
The collection of raw data in the field, field research, field study, field studies.
Work done out in the fields as opposed to that done elsewhere on the farm (e.g., barn, house, outbuildings, office).
Work done out in the real world rather than in controlled conditions