footbridge, levy, monopoly

榷 is composed of 木 (wood) and 隺 (crane-like water bird). 隺 is a pictograph depicting a water bird with a long beak; its slender, elongated shape resembles a single-log bridge. Thus, 榷 originally refers to a single-log bridge. This narrow log was the only connection between two places, making it an exclusive passage. The builder of the bridge could collect a toll from those who crossed it, so 榷 later extended to mean taxation, monopoly, or exclusive rights.