A shortage happens when there isn't enough of something that people need or want. During a paper shortage, stores run low on notebooks and printer paper. A water shortage means not enough clean water is available for everyone who needs it. A teacher shortage means schools struggle to find enough qualified teachers for their classrooms.

Shortages occur for different reasons. Sometimes demand suddenly increases: if everyone wants the same popular toy at once, stores might face a shortage before they can order more. Other times supply decreases: a drought can cause a food shortage by damaging crops. Natural disasters, shipping problems, or manufacturing delays can all create shortages.

The opposite of a shortage is a surplus, when there's more than enough of something. Shortages usually drive prices up because people compete for limited supplies, while surpluses often push prices down. When your school cafeteria runs short of chocolate milk, that's a minor shortage. Serious shortages of food, medicine, or fuel can cause real hardship for communities.