The conversion of resources. An expenditure is an event. Conversions of resources may take several forms: 1. Exchange: conversion of title or ownership (e.g., dollars for materials), 2. Consumption: conversion of a liquid resource to a less recoverable state, i.e., expenditures of time, human resources, dollars to produce something of value, or the incorporation of inventoried materials into fixed assets.

SOURCE: apm.com”