the.com/opportunity cost

means The value of the next-best option you give up when you choose something else — what you sacrifice, not just what you spend.

from A term born in economics, crystallized in the late 19th century by thinkers like the Austrian economist Friedrich von Wieser, who argued that the true cost of anything isn't just its price but the forgone alternative use of those same resources. 'Opportunity' here keeps its old sense of a fitting chance or occasion — the word traces back to Latin ob portum, roughly 'toward the harbor,' as in a wind blowing favorably into port. Economics bolted 'cost' onto it to make a quietly radical point: every yes is also a no to something else, and that unseen no has a price.