A replacement means a person or thing that takes the place of another. When your pencil breaks, you pull out a replacement from your backpack. When a soccer player gets tired, a replacement runs onto the field to continue the game.

Sometimes replacements are temporary: a substitute teacher is a replacement for your regular teacher who's out sick. Other times they're permanent: when you outgrow your shoes, you get replacements that fit better.

The word can also describe the act of replacing something. The replacement of old playground equipment with new structures happens when the old swings and slides become unsafe. A library might schedule the replacement of worn-out books with fresh copies.

Not everything can be easily replaced. A broken window has a simple replacement, but a best friend who moves away doesn't. Some things are irreplaceable because of their unique value: a championship trophy, a handwritten letter from your grandmother, or the first dollar your business ever earned. These items matter because of the specific memories and meaning attached to them.