身 has a striking origin: oracle bone forms show a person in profile with a swollen belly — a pregnant woman. The original meaning was "to be with child / pregnant body", which generalized to "body / self / one's person". Identical across 繁體 / 新字体 / 简体.

The etymology explains the modern semantic spread. 身 covers the physical body (身体, shēntǐ) and also the social self / identity / status: 身分 (shēnfèn / mibun, identity/status), 出身 (chūshēn / shusshin, origins/background — "from what body/family"), 自身 (zìshēn / jishin, oneself), 终身 (zhōngshēn, lifelong), 修身 (xiūshēn, self-cultivation). Confucian ethics treats 修身 as the foundation for governing a family, then a state, then the world.

Mandarin: shēn, level 1st tone. 身体 (shēntǐ, body / health), 身高 (shēngāo, height), 身边 (shēnbiān, beside one — "body-side"), 全身 (quánshēn, whole body), 单身 (dānshēn, single/unmarried). Also the measure word for outfits: 一身衣服 (yīshēn yīfu, "one outfit").

Japanese: on-reading シン (shin) in 身体 (shintai, body — formal), 身分 (mibun, social status), 自身 (jishin, oneself), 出身 (shusshin, hometown/origin — a Japanese cultural keyword). The kun-reading み (mi) is the everyday word — 身 (mi, body / oneself / flesh of fish), 中身 (nakami, contents — "inside body"), 親身 (shinmi, kindred). Pairs naturally with 心 to form 心身 (shinshin, mind and body).

Memory aid: a person standing in profile with a curved belly. The character is a body.