Plural of crasis; mixtures or blendings, especially of humors in medical theory or of linguistic elements in grammar.
From Greek krasis (mixing, tempering), derived from kerannynai (to mix). The Greek concept described both physical mixing in the body and grammatical contraction of sounds. Medieval and Renaissance scholars used this term in medicine and linguistics.
The ancient Greeks thought health depended on the perfect 'crasis' (blend) of your four humors—too much blood or bile made you sick. The same word described how Greek grammar lets vowels blend together, showing how one concept explained multiple phenomena.
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