1. a region in which explosives mines have been placed;
The Collaborative International Dictionary of English v.0.48:
minefield \minefield\ n.
1. (Mil.) a region in which explosive mines have been
placed, especially a region on land.
2. Hence: (Fig.) A situation in which a simple mistake can
have disastrous consequences; a touchy or dangerous
situation requiring great caution; as, the candidate
threaded his way skillfully through a minefield of loaded
questions from the audience.
WordNet (r) 3.0 (2006):
n 1: a region in which explosives mines have been placed