Retrospective term to describe music that influenced what would be coined as punk rock. It tended to be somewhat more aggressive than its contemporaries and often had anti-authoritarian themes.Such music included, The Velvet Underground, The Stooges, bands on the Nuggets compilation, The Sonics, The Seeds, The Monks, Patti Smith, The Dictators, New York Dolls, MC5, Richard Hell & the Voidoids, Neu!, etc. Not all influences of punk rock bands can be called protopunk. For example, Crass was influenced by experimentalist compser, John Cage, but nobody would call him a protopunk artist.
Iggy Pop got his start in a protopunk band called The Stooges.