Added 10 October 2026 biodiesel noun Categories: Rare Words noun ! Definition from Wiktionary (CC BY-SA). More about biodiesel at Wordnik → Where our words come from → Fuel for diesel engines made from renewable organic raw materials, as opposed to fossil hydrocarbons. Related Words: biofueldieselbiobio-dieselbiofuelsbiodervpetrodieselbiokerosenefarnesanebio-oilbioalkanebiobutanol Back to today's word