When something holds up, it continues to work well or stay strong over time. A well-made backpack holds up through years of heavy use, while a cheap one might fall apart after a few months. A scientific theory holds up when new experiments keep confirming it. Your excuse for missing homework might not hold up under your teacher's questioning if it has holes in the logic.

The phrase can also mean to delay or stop something temporarily. A traffic accident might hold up your family's road trip for an hour. If you hold up the lunch line by taking too long to decide what to eat, everyone behind you has to wait.

You might also hold something up physically, like holding up a sign at a parade or holding up your hand to answer a question. When you ask someone to hold up their end of a bargain, you're asking them to do their agreed-upon part of the deal.