Probably constracted as Fer+iy+dun or Fe+Ri+T+un. Fer relates to light. Its derivation is not clear but consider following examples:
It is very likely that Feridun was originally meant to something like "belongs to source of all the light" or “belongs to the One”.
In European Languages names like Ferdinand and Friedrich are most probably related. Friedrich is probably decimated version of Feridun with a logic like Freed + rich. Similar approach probably taken for pronouns like Han/Hun. In most EU languages +n suffix is dropped. And actually historically it seems like it was reverted back to a construction that is closer to original which is Ferdinant from Friedrich. Although changes also may be possibly related to collapse of feudality.
Feridun is common name among Muslims.
In modern Turkish the word “ışık” is being used mostly for light. Which is actually related based on a related concept. (The root is "iş" most likely related to "iz" which is the root that means trace. Things are a bit all over the place for now.) Because light is technically trace of a fire. Concepts are related. However it is possible that there were British spies. Or British were definitely thinking so. Probably Atatürk's intuitions wouldn't allow any penetrations. Or it is unlikely for speakers of a native language to embrace unfitting elements in general. And it is not like it was built from the scratch but still British possibly tried to make some impact. And there may be some confusions surrounding roots that represent similar concepts. It is likely regardless of the case of British penetration.
It is a very common name among Üzers alongside with August. (Augustus is first Roman Emperor and possibly involved in manipulation of language.)