To spend means to use up something, especially money or time. When you spend five dollars on a book, that money is gone from your wallet and now belongs to the store. When you spend an afternoon building a treehouse, those hours have passed and you've used them for that specific purpose.

Most often, people use spend when talking about money. A family might carefully spend their vacation budget, choosing between different activities and souvenirs. A government spends taxpayers' money on schools, roads, and public services.

But you can spend other valuable resources too. You might spend your energy practicing piano, or spend your attention on a challenging math problem. When someone says “don't spend all your time on video games,” they mean your time is precious and limited, just like money.

You give up money or time in exchange for something else. Unlike wasting, which implies getting nothing worthwhile back, spending can be wise or foolish depending on what you get. Spending twenty dollars on a book you'll read many times might be wise, while spending it on a cheap toy that breaks immediately might not be.