dispenseyoudaoicibaDictYouDict[dispense 词源字典]
dispense: [14] Dispense comes ultimately from Latin dispendere ‘weigh out’ (partial source of English spend). This was a compound verb formed from the prefix dis- ‘away’ and pendere ‘weigh’, a relative of pendēre ‘hang’, from which English gets pendulum, pendant, and penthouse. It had a derivative, dispensāre, denoting repeated action: hence ‘pay out, distribute’, senses which passed into English via Old French dispenser. In medieval Latin dispensāre also came to mean ‘administer justice’, and hence ‘exempt, condone’; this was the source of the English usage dispense with ‘do without’.
=> pendulum, pendant, penthouse, spend[dispense etymology, dispense origin, 英语词源]
spendyoudaoicibaDictYouDict
spend: [OE] Spend is a blend of verbs from two distinct sources, but both going back ultimately to Latin pendere ‘weigh, pay’. The earlier was Latin expendere ‘pay out’ (later to give English expend [15]), which Old English took over as spendan. (It was also the source of German spenden.) This was later reinforced by dispend, a borrowing from Old French despendre which now survives only in dispense.
=> dispense, expend, pendant, pendulum
dispense (v.)youdaoicibaDictYouDict
early 14c., from Old French dispenser "give out" (13c.), from Latin dispensare "disburse, administer, distribute (by weight)," frequentative of dispendere "pay out," from dis- "out" (see dis-) + pendere "to pay, weigh" (see pendant).

In Medieval Latin, dispendere was used in the ecclesiastical sense of "grant license to do what is forbidden or omit what is required" (a power of popes, bishops, etc.), and thus acquired a sense of "grant remission from punishment or exemption from law," hence "to do away with" (1570s), "do without" (c. 1600). Older sense is preserved in dispensary. Related: Dispensed; dispensing.
spend (v.)youdaoicibaDictYouDict
"to pay out or away" (money or wealth), Old English -spendan (in forspendan "use up"), from Medieval Latin spendere, a shortening of Latin expendere "to weigh out money, pay down" (see expend) or possibly of dispendere "to pay out." A general Germanic borrowing (Old High German spendon, German and Middle Dutch spenden, Old Norse spenna). In reference to labor, thoughts, time, etc., attested from c. 1300. Intransitive sense "exhaust, wear (oneself) out" is from 1590s (see spent).