detailyoudaoicibaDictYouDict
detail: [17] Etymologically, a detail is a ‘little piece cut off’. It comes from French détail, a derivative of détailler ‘cut up’. This was a compound verb formed from the intensive prefix dé- and tailler ‘cut’ (a relative of English tailor and tally). English acquired the word via the French phrase en détail ‘piece by piece, item by item’, source of the central modern meaning ‘individual item, particular’.
=> tailor, tally
mealyoudaoicibaDictYouDict
meal: [OE] Meal ‘repast’ and meal ‘flour’ are two distinct words. The former originally meant ‘measure’: it goes back via prehistoric Germanic *mǣlaz (source of German mal ‘time, occasion’ and mahl ‘meal’, Dutch maal ‘time, meal’, and Swedish mål ‘meal’) to the Indo-European base *me- ‘measure’, which is also the ancestor of English measure.

The semantic progression from ‘measure’ (which died out for meal in the Middle English period, but survives in the compound piecemeal [13], etymologically ‘measured piece by piece’) to ‘repast’ was via ‘measured or fixed time’ (hence the meaning ‘time, occasion’ in many of the related Germanic forms) and ‘time fixed for eating’. Meal ‘flour’ (as in oatmeal) goes back ultimately to Indo-European *mel-, *mol-, *ml- ‘grind’, source of a wide range of other English words from mild and mill to molar and mould.

From it was descended West and North Germanic *melwam, which has differentiated to German mehl, Dutch meel, Swedish mjōl, Danish mel, and English meal. It has been speculated that mellow [15] may have originated in the use of Old English melu ‘meal’ as an adjective, in the sense ‘soft and rich like flour’.
=> measure, piecemeal; mellow, mild, mill, molar, mould
detail (n.)youdaoicibaDictYouDict
c. 1600, from French détail, from Old French detail "small piece or quantity," literally "a cutting in pieces," from detaillier "cut in pieces," from de- "entirely" (see de-) + taillier "to cut in pieces" (see tailor).

Modern sense is from French en détail "piece by piece, item by item" (as opposed to en gros), a commercial term used where we would today use retail. Military sense is 1708, from notion of "distribution in detail of the daily orders first given in general," including assignment of specific duties.