Several parts combine into one character.

Compound character: 戶 (one-leaf door) + 斤 (axe). The original meaning was "the sound of an axe striking wood at a doorway" — but the character was reborrowed phonetically and now carries TWO unrelated abstract meanings: "place / location" + "the thing which / that which" (a relativizer). Identical across 繁體 / 新字体 / 简体.

The two meanings of 所 — concrete "place" AND abstract relativizer — both run through CJK languages.

Mandarin: suǒ, dipping 3rd tone. As a noun meaning "place": 住所 (zhùsuǒ, residence), 派出所 (pàichūsuǒ, police substation), 厕所 (cèsuǒ, toilet — formal). As a grammatical relativizer (one of the most important classical Chinese particles): 所以 (suǒyǐ, "the reason why" → "therefore" — extremely high-frequency conjunction), 所有 (suǒyǒu, "all that exists" → "all"), 我所喜欢的 (wǒ suǒ xǐhuan de, "what I like" — using 所 to nominalize a verb phrase). The grammatical 所 is one of the foundational classical Chinese functions still active in modern formal Chinese.

Japanese: on-reading ショ (sho) for compounds — 場所 (basho, place — already discussed), 住所 (jūsho, address), 役所 (yakusho, government office), 近所 (kinjo, neighborhood — high-frequency word for "the area near where I live"), 名所 (meisho, famous place / tourist spot). Kun-reading ところ (tokoro) is the everyday word — 所 (tokoro, place / situation), 私の所 (watashi no tokoro, my place / where I am). The suffix ~ところ adds situational nuance: 行くところ (iku tokoro, "the place to go" / "I'm about to go").

The Japanese 近所 (kinjo, "neighborhood") and 場所 (basho, "place") together cover most spatial conversation needs — both built on 所.

Memory aid: door + axe — etymology long forgotten, but the character now anchors "place" and "that which" across CJK abstract grammar.