To capitalize means to write or print a letter in its large, uppercase form. When you capitalize the first letter of your name, you write it as a capital letter: Sarah instead of sarah. English has rules about when to capitalize: always capitalize the first word of a sentence, people's names, the names of specific places, and the word “I.” Capital letters help readers instantly recognize when a new sentence begins or when you're referring to someone specific.

The word also means to take advantage of an opportunity. When a soccer player sees the goalie out of position, she might capitalize on the mistake by taking a quick shot. If you studied hard for vocabulary while other students didn't, you can capitalize on your knowledge during the test. This meaning suggests seizing a favorable moment: recognizing when circumstances give you an edge and acting on it quickly.

In business and finance, to capitalize can mean to provide money to start or grow a company, or to calculate the total value of something. When investors capitalize a new bakery, they provide the funds needed to buy ovens, ingredients, and rent space. A well-capitalized business has enough money to operate and weather difficult times.