What does DOU stand for?

Definitive Observation Unit - Medicine (MEDA)

Dolphin Dinghies Inc., Bellingham, WA - Manufacturer code for watercraft hull identification number (USCG)

Douglas - NCIC firearms make code (NCIC)

Dourados - Brazil - Airport symbol (OAG)

Dourbes - Belgium - Seismograph station code, US Geological Survey (SEIS)

Duala - Language code (ETLW)