场 = square, plaza, open space, field, market => 土 (earth) + a simplified form of 昜, which is used only as a character component and means ‘to open out, to expand’, as well as ‘bright or glorious’, and represents a picture of the sun above the horizon 旦 , i.e. 日 (sun) +  一 (ground), with its shadows 勿 (not), i.e. where the sun does ‘not’ shine

related: 田 , 方

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