Several parts combine into one character.

叔 originated with an unrelated meaning: a pictograph of a hand grasping bean stalks — "to gather beans / pick beans." The character's phonetic value was then borrowed for an entirely different meaning: "the third-born sibling, the smaller / younger one." Classical Chinese ranked siblings in a four-position system: 伯 (eldest), 仲 (second-born), 叔 (third-born), 季 (youngest). Where 叔 fell in this hierarchy as the third-eldest brother, the term extended to refer to "father's younger brother" — the paternal uncle who is junior to one's father.

This sibling-hierarchy system is one of the most consequential features of East Asian kinship vocabulary: every relative is positioned by age relative to one's parents, generating a precise terminological grid that English collapses into the single word "uncle."

Korean reading "suk." 叔父 (sukbu, father's younger brother — formal term), 叔母 (sukmo, the wife of father's younger brother), 小叔 (sosuk, husband's younger brother — for women), 伯仲叔季 (baekjung-sukgye, the four classical sibling positions). Korean traditional kinship vocabulary is dense with such terminologies; modern Korean has simplified some but retains the formal Sino-Korean compounds.

Mandarin shū, 1st tone. 叔叔 (shūshu, "uncle-uncle" = paternal uncle younger than father / friendly term for any middle-aged man) — the doubled form is everyday Mandarin, used by children to address adult male strangers in a friendly way (similar to Korean 아저씨 ajeossi). 叔父 (shūfù, formal paternal uncle younger than father), 伯叔 (bóshū, "uncle ranks" — collective term).

Japanese on-reading シュク (shuku) — 叔父 (shukufu, paternal uncle younger than father), 叔母 (shukubo, wife of father's younger brother). Japanese makes one of the most precise kinship distinctions in CJK: it splits "uncle" into TWO different kanji depending on relative age. 叔父 / 叔母 = parent's younger sibling. 伯父 / 伯母 = parent's elder sibling. Both pairs are read identically as おじ (oji, uncle) and おば (oba, aunt) in spoken Japanese — the kanji choice is a written-only distinction. When writing, however, the choice is mandatory and reveals careful attention to family structure. A child must know whether their uncle is older or younger than their parent to write the kanji correctly.

Memory aid: 叔 began as picking beans, was borrowed phonetically for "third-born / younger of the parental generation" = paternal uncle younger than father.