The word 港口 is formed by combining two characters, each contributing a core concept to create a new, unified meaning. The first character, 港 (gǎng), means "harbor" or a sheltered body of water for boats. The second, 口 (kǒu), literally means "mouth" or "opening". Together, they construct the idea of a "port" or "seaport" by metaphorically portraying it as the "harbor's mouth", the crucial opening or gateway where the protected waters of the harbor meet the open sea, and where vessels and goods pass through.