Definition of hackleback in English:

hackleback

noun

  • 1United States regional. A North American freshwater mussel, Lasmigona complanata, with rough ridges on the shell. Now rare.

  • 2Chiefly US (originally regional). The shovelnose sturgeon, Scaphirhynchus platorynchus, a small freshwater sturgeon of the Missouri and Mississippi river systems. Often attributive, especially with reference to the use of its black roe as caviar.

Origin

Late 19th century. From hackle + back.

Pronunciation

hackleback

/ˈhaklbak/