The term blockade is reserved here for coercion on the scale of states and sea communications, rather than any physical obstruction. A siege normally combines isolation with bombardment or preparation for an assault on a specific defended position. A blockade aims to stop goods, people, or revenue moving into or out of a target. It may be less immediately violent, but its duration and reach can make it a more persistent form of pressure. This distinction becomes important later when the video asks whether destructive submarine warfare is better understood as maritime siege warfare.
Notable Point · 5:44-7:19
Why a blockade is not the same as a siege
The video separates blockade from siege by contrasting control of movement and trade with the direct violence used to weaken and capture a defended place.