外 wài = 夕 (xī, evening) + 卜 (bǔ, divination). The left element 夕 is the pictograph of a crescent moon, marking dusk and the falling of night; the right element 卜 shows the crack that opens in a heated oracle bone or turtle shell, the sign the diviner reads. Divination was meant to be done in the morning, so to consult the shells in the evening was to act off the proper schedule, at an irregular, unsanctioned time. From that idea of "outside the norm" the character settles into its core meaning: outside, beyond, external.

From the boundary line, the senses fan out:

1. Outside, outer, exterior. Anything past the edge of a space: 外面 wàimiàn (outside), 户外 hùwài (outdoors), 国外 guówài (abroad), 外表 wàibiǎo (outward appearance).
2. Foreign, external. Outside one''s own country or group: 外国 wàiguó (foreign country), 外语 wàiyǔ (foreign language), 外卖 wàimài (takeout, food sent out from the kitchen).
3. Other, besides, in addition. Outside the matter already named: 另外 lìngwài (besides; another), 此外 cǐwài (apart from this), 除外 chúwài (to exclude).
4. Maternal relatives. Kin reckoned outside the patrilineal surname: 外婆 wàipó and 外公 wàigōng (maternal grandmother and grandfather), 外甥 wàishēng (sister''s son).

The thread through every sense is the line between in and out. Its constant partner and opposite is 里 lǐ (inside): wherever 外 marks what lies beyond, 里 marks what lies within, and the pair 里外 (inside and out) carries the whole of a space.

Stretch "outside" past the wall of a house to the wall of a country, and 外 becomes "foreign." 外国 wàiguó is a "foreign country," literally an "outside country," and a person from one is an 外国人 wàiguórén. The same 外 marks anything that comes from beyond one''s own borders or circle: 外语 wàiyǔ (a foreign language), 外资 wàizī (foreign capital), 外交 wàijiāo (diplomacy, the management of relations with the outside).

The sense also covers what is simply sent out rather than kept in. 外卖 wàimài, now the everyday word for food delivery, is literally "sell-out," a meal dispatched beyond the kitchen rather than eaten in. In every case 外 draws a circle and points past its edge: outside the home, outside the nation, outside the kitchen door.

The third path 外 takes is from spatial "outside" to logical "besides." If something stands outside the matter just named, it is an addition or an exception. 另外 lìngwài (另 "another" + 外 "outside") means "besides, in addition, another": 另外一个 "another one," or as a connector, 另外，我还想说一件事 "besides, there''s one more thing I want to say." Its formal cousin 此外 cǐwài means "apart from this."

The same logic gives 例外 lìwài (an exception, what falls outside the rule) and 除外 chúwài (to leave out, to exclude). And 外 reaches into kinship the same way: relatives on the mother''s side stood outside the father''s surname line, so they are marked 外, giving 外婆 wàipó (maternal grandmother), 外公 wàigōng (maternal grandfather), and 外孙 wàisūn (a daughter''s son).

Picture the diviner at dusk, 夕, cracking the shell, 卜, at the wrong hour, off the proper morning schedule. That single image, "doing it outside the normal time," is the whole character: outside, beyond, off the inside track.

Then draw a circle and step past its edge. Past the wall of the house, 外 is the outdoors (外面, 户外). Past the wall of the country, it is the foreign (外国, 外语). Past the kitchen door, it is the takeout (外卖). Past the matter at hand, it is the addition (另外, 此外). Past the father''s surname line, it is the mother''s kin (外婆, 外公). Whatever the circle, 外 is always the step beyond it, and its partner 里 is the step back in.