Wikipedia is telling me that θύμος and θυμός are two different words. But I am reading a book discussing Plato's theory of the tripartite soul that seems to be conflating them. When Plato is speaking of the θυμοειδές part of the soul, does he mean θύμος, θυμός, or are both implied?
thank you very much for your inquiry and interest in classical languages. The word θυμοειδές could in terms of grammar, indeed, be composed of both θύμος/θυμός. The barytone word θύμος is in fact out of context with regard to Plato's dialogue as it is a kind of plant (thyme; gland etc.). So, the part of the soul that he implies is what we have so far interpreted with "anger, ire, rage", all of which correspond to θυμός (cf. schizo-thymia).
I hope it is clearer now and I wish you all the best for the forthcoming New Year!
Do not hesitate to ask me again.