birchyoudaoicibaDictYouDict
birch: [OE] Old English bi(e)rce came from a prehistoric Germanic *berkjōn, source also of German birke. The word goes back ultimately to an Indo-European *bhergo, but as is often the case with ancient tree-names, it does not denote the same type of tree in every language in which it has descendants: Latin fraxinus, for example, means ‘ash tree’. It has been speculated that the word is related to bright (whose Indo-European source was *bhereg-), with reference to the tree’s light-coloured bark.

It could also be that the word bark [13] itself is related. The verb birch ‘flog’ (originally with a birch rod or bunch of birch twigs) is early 19th-century.
=> bark, bright
alcohol (n.)youdaoicibaDictYouDict
1540s (early 15c. as alcofol), "fine powder produced by sublimation," from Medieval Latin alcohol "powdered ore of antimony," from Arabic al-kuhul "kohl," the fine metallic powder used to darken the eyelids, from kahala "to stain, paint." The al- is the Arabic definite article, "the."

"Powdered cosmetic" was the earliest sense in English; definition broadened 1670s to "any sublimated substance, the pure spirit of anything," including liquids. Modern sense of "intoxicating ingredient in strong liquor" is first recorded 1753, short for alcohol of wine, which was extended to "the intoxicating element in fermented liquors." In organic chemistry, the word was extended 1850 to the class of compounds of the same type as this.