Fiftieth means number fifty in a sequence, coming after forty-ninth and before fifty-first. If you line up all the students in your school by height and you're the fiftieth person, that means exactly forty-nine students are shorter than you.

The word often appears in celebrations and milestones. A fiftieth birthday marks someone completing half a century of life. A fiftieth anniversary, called a golden anniversary, celebrates fifty years of marriage or fifty years since an important event. Countries celebrate their fiftieth year of independence, businesses celebrate fifty years in operation, and when the United States welcomed its fiftieth state into the union (Hawaii in 1959), that was a fiftieth state celebration.

You'll also encounter this word in fractions: one fiftieth means dividing something into fifty equal parts and taking one of them. If fifty friends equally split the cost of a pizza party, each person pays one fiftieth of the total bill.

Notice how fiftieth is spelled: it's fiftieth, not “fiftyeth.” The y in fifty changes to i, and we add eth instead of th. The same pattern works for other multiples of ten: sixtieth, seventieth, eightieth.