D1UK, then D1GB (as former official franchise to D1GP), known now as European Drift Championship in the United Kingdom

D1 IRL, known now as Prodrift Irish Series in Republic of Ireland

ironic reference to "one sided"-die which gives the "random" value 1 when used.

A hexadecimal value equal to the decimal value 209

D-1 152 mm howitzer - a Soviet World War II artillery system.

The German D1 mobile phone network, currently known as T-Mobile

The D1 Dopamine receptor

In town and country planning in the UK, D1 is the code for permission to use specific land or premises for non-residential institutions (schools, libraries, surgeries).

Y-DNA Haplogroup D1

D1 (Sony) (An early digital video recording format)

AEG D.I, a German World War I fighter

D1 Recordings, a record label

Highway D1 in the Czech Republic

Highway D1 in Slovakia

The D1 Grand Prix or D1GP, the premier car drifting championship in the world.

D1NZ from New Zealand

Dolem - beings found in the anime series RahXephon

Division I NCAA sports

Nikon D1, a DSLR