"Hicieron" is the third-person plural form of the verb "hacer" in the preterite tense, which means "to do" or "to make" in English. It is used to describe actions completed in the past by a group of people. For example, if a group of friends completed a project, one might say, "Ellos hicieron un gran trabajo," meaning "They did a great job." In Spanish, the preterite tense is often used to narrate specific events or actions that have a clear beginning and end. "Hicieron" can be used in various contexts, such as describing activities, tasks, or accomplishments. For instance, "Los estudiantes hicieron una presentación" translates to "The students made a presentation."