户外
hùwài · HSK 6
outdoor
🏕️🌳 户 door + 外 outside = beyond the door, outdoors
A 户 is a single-panel door (half of 门). Once you step 外 outside that door, you are 户外 — in the open air. The word literally spells out leaving the house.
户 — single-leaf door (half of 門)
户 is a pictograph showing a single-leaf door, originally drawn as half of 門 (a double door). It came to mean 'door,' then by extension 'household' or 'family,' since a door marks one dwelling. Today it commonly means 'household' or 'account.'
外 — evening 夕 + divination 卜
Originally a compound of 夕 (evening) and 卜 (divination). Ancient Chinese divinations were performed in the morning; doing them at evening (夕) was considered irregular or 'outside' the norm. From this sense of deviation, 外 came to mean 'outside' or 'external'.