robi-

Today it means: The IEC prefix meaning 2⁹⁰ = 1,024⁹ = 1,237,940,039,285,380,274,899,124,224. Compare ronna-, meaning 10²⁷ = 1,000⁹ = 1,000,000,000,000,000,000,000,000,000, an octillion. Full definition →