买卖 (mǎi mai) is a colloquial noun for 'business, trade, or a transaction,' commonly used in spoken Chinese (e.g., 做买卖). It is more concrete and deal-specific than 商业 (shāng yè 'commerce as a field') and less formal than 交易 (jiāo yì 'formal transaction'). Compared to 生意 (shēng yi), 买卖 often emphasizes the act of buying and selling itself.