What is the Spanish word for the number 21?

The Spanish word for the number 21 is "veintiuno." This term is formed by combining the root for twenty, "veinte," with "uno," which means one. In Spanish, numbers in the twenties are generally constructed as a combination of "veinte" followed by the unit digits. Therefore, the construction of "veintiuno" specifically represents the number 21.

While the other options represent numbers in the twenties, they refer to 22, 23, and 24, respectively. Understanding the pattern of counting in Spanish helps in distinguishing between these numbers and accurately identifying "veintiuno" as the correct answer for the number 21.