专业户 refers to a rural household that specializes in one industry or trade (e.g., farming, aquaculture, poultry-raising, or handicrafts) as its main source of income — a concept that emerged during China's Reform and Opening Up in the 1980s when the government encouraged peasant households to focus on a single commercial activity. It is a historical-economic term specific to Chinese development policy, not a direct synonym for 'professional household' in English.