Definition of head-foot in US English:

head-foot

noun

Zoology
  • (In molluscs) the soft structure lying below or anterior to the visceral mass, consisting of the head merging into the protrusible foot (in a gastropod) or into the tentacles (in a cephalopod).

Origin

1920s; earliest use found in Encyclopaedia Britannica. From head + foot, after head-footed.