A premise is a starting idea that you assume to be true when building an argument or creating a story. In logic and debate, premises are the foundational statements you use to reach a conclusion. If your premise is “All mammals have hair” and you add “Dogs are mammals,” you can conclude that dogs have hair. Your conclusion only works if your premises are actually true.

In storytelling, the premise is the basic setup or central idea that drives everything else. The premise of The Lion King is “A young lion must reclaim his rightful place as king after his father's death.” The premise of Charlotte's Web is “A spider tries to save her friend, a pig, from being killed.” Writers build entire plots, characters, and themes around these core ideas.

You'll also hear “premise” used when discussing buildings or property. A store owner might ask someone to “leave the premises,” meaning to exit the property or building. In this case, premises refers to a specific location and all the land or rooms that belong to it.

When people evaluate an argument, they examine the premises carefully. Even strong reasoning falls apart if it starts from a faulty premise. If someone argues that “all snakes are poisonous, so that garden snake is dangerous,” their premise is wrong, and their conclusion can't be trusted no matter how logical everything else sounds.