the word 'yen' for the japanese currency entered english in the late 19th century, directly from japanese 'en', meaning 'round', referring to the round shape of the coins. this japanese term itself is a borrowing from chinese 'yuan', which also signifies a round object or monetary unit. the distinct meaning of 'yen' as a 'strong desire' has a completely separate origin; it is believed to derive from a dialectal chinese word (such as cantonese 'yan', meaning 'craving') or possibly from an older english dialect word 'yene' or 'yern', meaning 'to desire eagerly'. the convergence of these two unrelated words into the identical english spelling 'yen' is a classic example of a homograph, where distinct etymological paths lead to a shared modern form.

this word is a loanword and is not productively formed from separable morphemes within the english spelling system.