The kanji 叔 primarily means "uncle" (specifically, the younger brother of one's father) or "father's younger brother." It can also extend to represent a familial relationship with someone of a similar age and perceived position to an uncle.

・On-yomi (音読み): シュウ (shuu) ・Kun-yomi (訓読み): None, because there is no specific native Japanese word for "uncle" younger than one's father.

⚫︎叔父 Translation: Uncle (father's younger brother) ⚫︎叔母 Translation: Aunt (father's younger sister or brother's wife) ⚫︎叔父さん Translation: Uncle (a more casual and polite term)

The kanji 叔 is a phono-semantic compound (形声文字). It is composed of two parts: a radical and a phonetic component. The radical is 又 (again) which shows relationship, and the phonetic component is 小 (small). The original meaning of 叔 was "younger brother," and the "small" part may have referred to a younger sibling, or be associated to relative age. The character developed into the more specific meaning of "father's younger brother" over time.