Wow, you learn something new every day (even if it’s not Japanese-related).
The name geoduck is derived from a Lushootseed (Nisqually) word gʷídəq [5][6] either a word composed of a first element of unknown meaning and əq meaning “genitals” (referring to the shape of the clam),[7] or a phrase meaning “dig deep”,[8] or perhaps both, as a double entendre. (Wikipedia)
So it’s actually a geo-dick.