The term "polymer" derives from the Greek word and refers to large molecules whose structure is composed of multiple repeating units, from which originates a characteristic of high relative molecular mass and attendant properties. The units composing polymers derive, actually or conceptually, from molecules of low relative molecular mass The term was coined in 1833 by Jöns Jacob Berzelius, though with a definition distinct from the modern  IUPAC  definition The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger,[11] who spent the next decade finding experimental evidence for this hypothesis