面 draws an eye (目) within the outline of a face (a 囗-like border) — the face's outline with the eye inside expressing "face, countenance." From there the meaning broadened to "surface, side, aspect, a plane," and the sense of a "mask" covering the face arose too.

Korean hanja-sound "myeon": 表面 (pyomyeon, surface), 場面 (jangmyeon, a scene), 方面 (bangmyeon, a field / direction), 假面 (gamyeon, a mask), 面接 (myeonjeop, an interview), 側面 (cheungmyeon, a side), 體面 (chemyeon, face / dignity). The Korean administrative unit 面 (myeon, below a county) is also this character.

Mandarin: miàn, 4th tone. 面包 (miànbāo, bread), 面条 (miàntiáo, noodles), 见面 (jiànmiàn, to meet), 方面 (fāngmiàn, aspect), 表面 (biǎomiàn, surface), 面子 (miànzi, face / dignity). In simplified Chinese 麵 (flour / noodles) merged into 面, so the modern 面 carries both "face / surface" and "flour / noodles" — 面包 (bread), 拉面 (ramen).

Japanese: on-reading メン (men), kun おも (omo), おもて (omote), つら (tsura). 表面 (hyōmen, surface), 場面 (bamen, a scene), 面接 (mensetsu, an interview), 仮面 (kamen, a mask), 面白い (omoshiroi, interesting). The Japanese 面白い (omoshiroi) originally came from "the face (面) brightening."

Memory aid: an eye (目) inside the outline of a face — from countenance to surface and aspect.