1769, "act of expending," from Medieval Latin expenditus, irregular past participle of Latin expendere "to weigh out; to pay out" (see expend) + -ure. Meaning "that which is expended" is from 1791. Related: Expenditures.
"to spend, pay out; to consume by use, spend in using," early 15c., expenden, from Latin expendere "pay out, weigh out money," from ex "out, out of" (see ex-) + pendere "to hang, cause to hang; weigh; pay" (from PIE root *(s)pen- "to draw, stretch, spin"). For the financial sense of the Latin verb, see pound (n.1). Related: Expended; expending.