Several parts combine into one character.

A character with three different forms across CJK scripts: — 繁體 (and Korean): 窗 — 穴 (hole / cave) above 囪 (chimney / smoke vent in roof). — 新字体 (Japanese): 窓 — 穴 above 厶+心 (a simplification placing 心 / heart at the bottom). — 简体 (Mainland China): 窗 — same as traditional, kept the chimney form.

The Japanese 心-bottom variant gives the character a poetic reading: "the hole through which the heart looks out / where light enters the mind". This is a Japan-specific etymological resonance not available in Chinese.

The semantic root: a window is fundamentally a "hole-in-the-wall" — a gap that lets in light and air. Compare 穴 (cave) which is wholly underground vs 窓 / 窗 which is wall-mounted.

Mandarin: chuāng, level 1st tone (simplified 窗 — but 窗 is also the traditional form). 窗户 (chuānghu, window — the everyday word, neutral final tone), 窗口 (chuāngkǒu, window / counter at a bank or government office), 玻璃窗 (bōli chuāng, glass window), 同窗 (tóngchuāng, classmate — same etymology as Korean 동창).

Japanese: on-reading ソウ (sō) for compounds — 同窓会 (dōsōkai, alumni reunion — "same-window meeting" — a major Japanese social ritual where former classmates gather years later), 車窓 (shasō, car / train window). Kun-reading まど (mado) is the everyday word — 窓 (mado, window), 窓口 (madoguchi, service counter — every Japanese government office, train station, and bank uses this term). The Japanese verb 窓を開ける (mado o akeru, "open the window") is foundational vocabulary.

The metaphor "classmate = same-window" — both Korean 동창 and Japanese 同窓会 — captures the shared experience of looking out the same classroom window during years of school.

Memory aid: hole + heart = the wall-opening through which the heart sees out.