Several parts combine into one character.

司 is a remarkable character: it is essentially the mirror image of 后 (hòu, "queen / behind"). The pair 后 / 司 captures a complete administrative dynamic — 后 depicts a ruler facing forward issuing commands from above, while 司 depicts a subordinate facing the opposite direction, receiving and executing those commands. The composite reads as "one who takes charge / receives the order to manage / official with delegated responsibility."

Korean reading "sa." 司會 (sahoe, "host" or "chairperson" of a meeting / event — used in TV programming as MC), 上司 (sangsa, superior / boss — used in workplace contexts: 직장 상사 jikjang sangsa "workplace superior"), 司令官 (saryeonggwan, commander — military), 司法 (sabeop, judiciary). The Sino-Korean compound 公司 (gongsa) for "company" is mostly used in Chinese-influenced names; modern Korean prefers (hoesa, 會社).

Mandarin sī, 1st tone. 公司 (gōngsī, "public office / company" — the standard Mandarin word for "company / corporation," used universally in business: 有限公司 limited liability company), 上司 (shàngsi, superior / boss), 司机 (sījī, "machine-manager" = driver — universal Mandarin word for taxi drivers, bus drivers, etc.), 司法 (sīfǎ, judiciary). The Mandarin word for company is 公司, distinct from Korean 회사 / Japanese 会社 — same concept, different compound.

Japanese on-reading シ (shi) — 司会 (shikai, MC / host), 司令 (shirei, command), 上司 (jōshi, superior / boss). And the global culinary export: 寿司 (sushi) — written 寿 (good fortune) + 司 (take charge), but this kanji compound is purely ateji (phonetic borrowing) for the native Japanese word sushi. The actual etymology of sushi traces to the verb 酸し (sushi, "to be sour" — referring to the vinegar used in preparing the rice). When the dish became globally famous, sushi traveled the world keeping its original Japanese phonology.

Memory aid: 后 (issuing commands from above) and 司 (mirror image, taking commands) are complementary characters of the East Asian administrative grid.