Eighth means coming after seven other things in order, like being the eighth person in line or living on the eighth floor of a building. When you write it as a number, you use 8th.

An eighth is also one of eight equal parts of something. If you slice a pizza into eight pieces, each slice is one eighth of the whole pizza (written as 1/8). If you have two slices, you have two eighths. Musicians use the term eighth note for a note that lasts one eighth as long as a whole note.

Notice the tricky spelling: even though eight has a g, eighth keeps it, making it one of those words where you see more letters than you hear when you say it out loud.

When you're in eighth place in a race, seven people finished ahead of you. When your birthday falls on the eighth of June, it comes on June 8th. And if your teacher asks you to open your book to the eighth chapter, you'll turn past the first seven chapters to find it.