「工業 (こうぎょう)」 refers to the manufacturing industry or industry in general, involving the large-scale production of goods in factories. It's a broad term for economic activities related to making physical products. For example, 「この国は工業が盛んです。」 (This country's industry is prosperous.)

物を作る工場などの産業全般を指します。例: この国は工業が盛んです。