Which of the following is the correct Spanish word for the number eighteen?

The correct Spanish word for the number eighteen is "dieciocho." This term is derived from the combination of "dieci-" which means ten and "ocho," which means eight. Thus, when combined, they literally translate to "ten and eight," making "dieciocho."

In the context of Spanish numbers, understanding the structure is crucial. Numbers between sixteen and nineteen follow the pattern where "dieci-" is added to the numbers six, seven, and eight to represent sixteen (dieciséis), seventeen (diecisiete), and eighteen (dieciocho) respectively. This helps in recognizing the progression and formation of these numbers within the Spanish language.

The other options do not represent eighteen: "dieciséis" is sixteen, "diecisiete" is seventeen, and "quince" is fifteen. Familiarity with the patterns can enhance fluency and comprehension in understanding numerical terms in Spanish.