Some Coromines' Spanish etymologies (the ones found in the DRAE are generally nastier) enjoy a greater credit than they actually deserve. For example, if we look at cerrar 'to close, shut' in his Breve diccionario etimológico de la lengua castellana, we can see he derives it from late Latin *serare < Latin sera 'bolt, lock', in spite that Spanish /c/ (in the Middle Ages a dental affricate [ts] and now an interdental fricative [θ]) can't come from Latin /s/. He denies elsewhere any relationship between this word and Catalan serrar, French serrer 'to tighten', although they fit both phonetically (as [ts] > [s] in these languages) and semantically (the meanings 'closed' and 'tight, dense' are related). The answer is all these words1 are Pyrenaic (a Vasco-Caucasian substrate language) loanwords from the PNC root *=utɕE(rV) 'thick, fat'.
Another weird etymology is jara 'rockrose (Cistus)', a kind of bush common in the Iberian Peninsula which Coromines derives from Arabic šacra 'low bush', where [ʃ] /x/ regularly developed into [χ] /j/. Apparently, he ignores Basque zare 'basket' and (t)xara 'rockrose (wood)', a word of Pyrenaic origin for which Bengtson suggests an etymology from PNC *tʃ’ʃ’wɦeli (˜ tɕ’ɕ’,-ʕ-,-ɫ-) 'a k. of foliage tree'2. The palatized form would have been borrowed into Spanish xara, then jara.
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1 There's also Basque (Biscayan) zarri 'dense', zarra-tu 'dense; to close, shut'.
2 Related to Paleo-Eurasian *tʃwalV 'willow', a root represented in Paleo-European *sal(i)k- 'willow' (Celtic *salik-, Latin salix, Germanic *salx-) and native IE *welik- 'willow' (Greek helíkē, English willow).
2 Related to Paleo-Eurasian *tʃwalV 'willow', a root represented in Paleo-European *sal(i)k- 'willow' (Celtic *salik-, Latin salix, Germanic *salx-) and native IE *welik- 'willow' (Greek helíkē, English willow).
