a type of rain hat having a broad back flap, usually worn with an oilskin raincoat.
1894  In a few minutes she is back, bearing with her a seaman's Cape Ann hat.
1936  (1966)  Oh, this is the place where the fishermen gather, / In oilskins and boots and Cape Anns battened down.
1958  One August day back in 1928 a teen-age boy, dressed in 'cape ann" and oilskins, was among those who were out on the squid jigging grounds at Change Islands.