In simple slang, economics is the science of making ends meet or the study of how that's done. But the slang phrase, making ends meet, is too habitually tied in people's minds to money, which is not even a necessary factor.
More exactly and in perfect English, economics is the study of how the actual availability of resources transformable into goods and services and the consumption of goods and services are or can be balanced and managed so that EITHER enough resources are found or developed and appropriately distributed as goods and services to meet and continue to meet all consumption needs OR consumption is modified and limited to avoid exceeding the actual availability of resources. That's economics.
If money is used as a dynamic bookkeeping tool to measure and limit each consumer's fair share of the goods and services distributed (as so-called salaries are used in Cuba) or to compare the value of goods and services traded or appropriately control the pace of production, then the use of money becomes a subtext of the science of economics and must be studied as a subtext, but neither money nor even trade is necessary in an economic system.
The noun economy and the modifiers economic and economical most accurately refer to an individual's or group's practice of using no more resources than are continuously or currently available, including raw materials, labor, goods, and services. The phrase THE economy is bad grammar which may be a semi-legitimate effort to avoid a heavier construction like the economic system, process, procedure, or situation but, if it refers only to the games played with i.o.u.'s and promises and money by Wall Street insiders, besides being bad grammar, it represents a deliberate or instinctive effort to fool the public.
The either cunningly planted or clumsily misbegotten idea that economics is only about the flow of money in and out of lucky and unlucky pockets, along with the pretense that stock market gambling is useful to everyone is a smoke-and-mirrors trick to cover high crimes and usury (see Capitalism); and editorial page "experts" who know nothing about mining, construction, agriculture, transport or anything else but the Wall Street numbers game cleverly called trade are either charlatans covering for the crooks or crooks themselves. The methodology of insiders who profit, i.e. get and keep control of more than their fair share of available resources or of the paper chits supposedly representing those resources may be a science, but it is not the science of economics. It could be a sub-text of sociology headed chicanery. In fact, it's a warped sub-text of economics headed capitalism.
But it's only a warped sub-text. Another more honest sub-text is communism, which may but doesn't have to have ANYTHING to do with money or profit or business. And another preferably temporary sub-text is socialism, which is a transitional purifying phase leading away from barbaric capitalism toward civilized communism. Socialism may have more or less to do with money or profit or business (or witchcraft) depending on how far the transition has gone and what route it takes.
If YOU can read and write coherently, it should take you no longer than an hour on the internet to discover that socialism is a near impossibly confused concept, especially in the minds of the apparently always language challenged people attempting to explain it. I don't know if this is inevitable, but I think the remedy is to move from capitalism to communism by the quickest means that can be devised.
Economics, in a household or a civil state, is the science or common sense practice of monitoring and balancing available resources with the production and use of goods and services with the intent of keeping things approximately even. A stable economic process should actually stay a little better than even, producing just enough surplus product to avoid shortages. A profit is an aberration which may be used as an honest hedge but which may also represent wasted resources and work and which, if it goes into a private pocket, is probably a crime. The regularly profitable business of an individual masquerading as a participant in a civilized state but actually getting the better of his neighbors, then, is the equivalent of ongoing bank robbery.