The compound word "表妹" (biǎomèi) is formed through a logical morphological structure common in Chinese kinship terminology, where the first character "表" acts as a modifier indicating a cousin relationship that is "external" or outside the immediate paternal lineage, specifically denoting cousins related through sisters (either one's father's sisters or one's mother's siblings). The second character, "妹", means "younger sister". Therefore, when combined, "表妹" precisely specifies "a younger female cousin" from these external family branches, creating a term that is both semantically transparent and systematically integral to the detailed framework of Chinese familial address.