A shortened or informal term relating to the skull; sometimes used as a variant or prefix in medical terminology.
From Greek 'kranion' (skull), shortened or used as a standalone combining form. This appears more commonly as a prefix (cranio-) than as an independent word in modern usage.
Craniol is rare as a standalone word, but it shows how medical terminology creates shortened versions for convenience—cranio- works perfectly as a prefix, which is why you see 'craniology' instead of 'cranioscience.'
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