What does D2 stand for?

Disrupt/Destroy (MLEX)

Angola - Aircraft nationality and registration mark (FAAC)

Data Distribution (SAUS)

Dicke des zweiten Farbfilters (SAUS)

Dud Disposer (SAUS)

Moderate Damage - Emergency Management (EMA)

Second Coast Guard District - St. Louis, MO - USCG (TAG)