This is the adjective for the small-picture study of an economy: one person choosing what to buy, one shop setting a price, one company deciding how many people to hire, one market for one thing. That study itself is called microeconomics; microeconomic is the word you put in front of other words — a microeconomic question, a microeconomic model, microeconomic policy. It is a school, university, and news word, quite formal. You almost never hear it in street talk. Economists pair it with macroeconomic, which looks at the whole country at once (prices rising everywhere, how many people have jobs, how much the country makes in a year). Though actually, a change that starts in one market — a tax on one product, a new rule for one industry — can roll outward and become a whole-country story; the tidy split is tidier than real life. Micro- here does not mean “unimportant.” It means “looked at in small pieces.”

個體經濟的（台灣學「個體經濟學」；中國大陸多說「微觀經濟的」）