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charcoal [charcoal 词源字典]: charcoal: [14] The words char and charcoal are related, but not in the way commonsense might lead one to suppose: for the verb char [17], originally apparently a charcoal-burner’s term, appears to derive from charcoal. So etymologically, the element char has nothing to do with ‘burning’. There are two main suggestions as to charcoal’s origins: firstly that it comes from Old French charbon ‘charcoal’ (related to English carbon); and secondly that it represents the now obsolete English verb chare (see CHARWOMAN), which in Old English times (cerran) meant ‘turn’.

On the basis of this theory, the etymological meaning of the word would be ‘turning into charcoal’ (for in Old English, coal meant ‘charcoal’ as well as ‘coal’).
[charcoal etymology, charcoal origin, 英语词源]
common sense (n.): 14c., originally the power of uniting mentally the impressions conveyed by the five physical senses, thus "ordinary understanding, without which one is foolish or insane" (Latin sensus communis, Greek koine aisthesis); meaning "good sense" is from 1726. Also, as an adjective, commonsense.