主 zhǔ is a pictograph of a flame burning on a lamp-stand. The oracle-bone and bronze forms show a tall stand with a single point of fire resting on top. That top dot, classed under the radical 丶 (zhǔ, "dot"), is the flame itself; the strokes below are the body of the lamp. The lamp was the steady central light of a room, and from that fixed, presiding point came the idea of the one in charge: the master of the house, the host who keeps the hearth.

From the central light four senses radiate outward:

1. Master, owner, host. The one who presides: 主人 zhǔrén (master; host), 房主 fángzhǔ (homeowner), 主席 zhǔxí (chairman; the one at the head of the table).
2. Main, primary, principal. The central thing among many: 主要 zhǔyào (main), 主题 zhǔtí (theme), 主意 zhǔyi (idea).
3. To be in charge, to decide, to advocate. The master's act of deciding: 做主 zuòzhǔ (to decide), 主持 zhǔchí (to host; to preside), 主张 zhǔzhāng (to advocate).
4. The Lord, a deity. The supreme master in religion: 主 zhǔ is how Chinese Christians address God, and 天主 Tiānzhǔ ("Lord of Heaven") names the Catholic God.

The thread through every sense is the presiding center. Whether the field is a household, a meeting, an argument, or the heavens, 主 is the one fixed point that holds authority, the flame at the middle of the room that everything else arranges itself around.

The master's defining act is to decide. 做主 zuòzhǔ is to "act as master," to be the one who settles a matter: 这件事你做主 "you make the call on this." From the same root comes 主持 zhǔchí, to preside over or host an event, the verb behind every emcee and chair. And 主张 zhǔzhāng is to advocate, to put forward and stand by a position: as a verb it means "to maintain," as a noun it means "a stance," the view one has decided to hold.

The same character anchors the political word 民主 mínzhǔ, democracy, literally "the people as master." Where a 君主 jūnzhǔ (monarch) is the single presiding master of a state, 民主 hands that mastering role to the people themselves. The flame that once meant the one in charge of a household scales all the way up to who holds authority over a country.

See the single flame resting on its stand: the top dot is the fire, the strokes below are the lamp. That steady central light is the whole character. Everything 主 means is the one presiding point that the room arranges itself around.

In a household, that point is the master and host (主人). Among many things, it is the main one (主要). In a meeting, it is the one who presides (主持). In an argument, it is the position one holds and stands by (主张). In a state, it is who holds authority, whether a single monarch (君主) or the people themselves (民主). Whenever you meet 主, look for the presiding center, and you will find the flame on the stand.