zeptojoule

noun1

1. •
   An SI unit of energy equal to 10⁻²¹ joules. Symbol: zJ

   • The associated work is W = 38.5 nm² × (10⁻⁹m/nm)² 35 pN/μm (10⁻¹² N/pN) (μm/10⁻⁶ m) = 1.35 × 10⁻²¹ J or about one zeptojoule. — 2012