Geoduck (1882) origin

[Fritz Juengling]

Here's what Mathews has to say in the DA page 690:

No doubt from a Nisqualli Indian term meaning "dig deep."  See Webster s.v.
_gweduc_.  In _Natural History_. April 1948, 190, the name is said to be
based on that of a certain John F. Gowey.  The pronunciation given here is
the one said to be correct on p. 163 of the magazine cited, but _Cent. Supp.,
s.v. goeduk_, has ['goid^k].

Of course, this still does not answer the question of why it is spelled as it
is.

Fritz Juengling