Added 9 October 2026 nanojoule noun Categories: Obscure Words noun ! Definition from Wiktionary (CC BY-SA). More about nanojoule at Wordnik → Where our words come from → An SI unit of work or energy equal to 10 joules. Symbol: nJ Related Words: nano-joulemegajoulezeptojouleattojoulejoulepetajoulefemtojoulekilojoulezepto-jouleterajoulenanovoltmega-joule Back to today's word