The prefix "deca-" comes from the Greek word "deka," meaning ten. It is commonly used in the metric system to denote a factor of ten. For example, a decameter is ten meters, and a decagram is ten grams. This prefix helps simplify measurements and calculations in various scientific fields. In addition to its use in the metric system, "deca-" appears in various contexts, such as in decathlon, which is a combined event in athletics consisting of ten track and field events. Understanding this prefix can enhance comprehension of numerical relationships in everyday life and academic subjects.