Priceless means so valuable that no amount of money could properly measure its worth. Your grandmother's handwritten recipe cards might be priceless to your family, not because they'd sell for millions, but because they carry memories and connections that money simply can't buy. A museum might display a priceless ancient artifact, meaning it's so rare and historically important that putting a dollar amount on it seems almost ridiculous.

The word has a wonderful logic to it: something without a price because it's worth more than any price, not less. Your first drawing that your parents saved, a letter from someone you love, a photograph of a special moment: these things are priceless because replacing them would be impossible, no matter how much money you had.

People also use priceless more casually to describe something hilariously funny or perfectly timed. When your little brother walks into the room wearing his shirt backwards and inside out, completely unaware, you might say “his expression was priceless” when he finally noticed. In this lighter sense, it means something so amusing or memorable that it creates a moment you'll treasure and laugh about for years.