I’m not really a coffee drinker. I’d love to be, as it would give me one more thing to be snobby about. But for now, I’ll stick to cufflinks and Savile Row suits. In any case, according to Wikipedia, coffee was introduced around the 15th or 16th century, so it’s fairly recent and there is, therefore, no Koine Greek word for it. It thus provides an interesting test case or thought experiment for how we can describe modern things using an ancient language.
In modern Greek, coffee is ὁ καφές. This is probably a loan word from Turkish kahve, which explains the –ές ending, fairly rare in modern Greek (from what I can tell, most –ές nouns are recent loan words from Turkish, French, etc.). According to the Greek Wiktionary, which is an easy and helpful resource for modern Greek, καφές is a third declension noun. The nominative plural form is καφέδες.
1. We can treat the word as an indeclinable loan word. We would still, however, need to be able to distinguish between singular and plural. I suppose we could simply transliterate the Turkish plural.
2. We could totally Koine-ize the word. As far as I know, third declension nouns ending in –φές are unknown in Classical or Hellenistic Greek, so we would slightly adjust it to καφίς. We would also use a full Classical declension, thus the genitive would be καφίδος rather than the modern καφέ. One problem with this is that 3rd declension nouns with a dental stem (καφίδ-) are uniformly feminine (please correct me if I’m wrong), so we’d need to change the gender of the noun from masc to fem.
3. We could leave it as a foreign sounding loan word, but give it a full Classical-ish declension. Thus, καφές, καφέδος. No need to change the gender, then.
What do you think? Any other options you can think of? Let us know in the comments below!
Update (2/1/12): Make sure to read the comments below, especially the rather detailed ones by Grigoris: https://danielstreett.wordpress.com/2012/01/20/coffee-in-koine-greek/#comment-619 and https://danielstreett.wordpress.com/2012/01/20/coffee-in-koine-greek/#comment-621