y doing the work of i
polipodium or polypodium?
polypodium. The second letter of the word is y.
y doing the work of i
poly is one of the most heavily used Greek prefixes in English, and it is written the same way every time: polygon, polymer, polythene, polyphony. It means many. Here it counts the feet, and it keeps the y that marks it as Greek. An i in that position leaves the prefix unrecognisable, which matters more than it sounds like it should, because poly is the half of the word most people can spell without thinking.
The class
A Greek upsilon, written y in English and sounding like a plain i.
Same name
Other spellings recorded for polypodium
The name