The word "婶母" is formed by combining the character "婶", a phono-semantic compound comprising the radical "女" (female) for meaning and the component "审" for sound, with the character "母" (mother), which is pictographic in origin. This combination yields a compound word where "婶" denotes the specific familial role of the wife of a father's younger brother, and "母" emphasizes the maternal or aunt-like relationship, collectively referring to a paternal aunt by marriage.