The word "广阔" (guǎngkuò) is a **synonym compound**, formed by combining two characters with closely related meanings to create a more vivid and emphatic single concept. The first character, **广** (guǎng), primarily means "wide" or "vast" in a spatial sense, while the second character, **阔** (kuò), means "broad," "expansive," or "open." When paired, they reinforce and amplify each other, resulting in a term that conveys a profound sense of vast openness, such as that of a landscape, sky, or field, effectively meaning "vast and broad."