From Wiktionary, the free dictionary
From drei (“three”) + Rad (“wheel”).
Dreirad n (strong, genitive Dreirads or Dreirades, plural Dreiräder)
- tricycle, trike
Declension of Dreirad [neuter, strong]
- “Dreirad” in Duden online
- “Dreirad”, in Digitales Wörterbuch der deutschen Sprache[1] (in German)