Which term is associated with speed at sea?

The term "knot" is the correct answer because it is a unit of speed that is specifically used in maritime and aviation contexts to measure the rate at which a vessel or aircraft travels. One knot is defined as one nautical mile per hour, which emphasizes its connection to navigation and the vastness of the ocean, where distances are more commonly measured in nautical miles rather than standard miles. The usage of knots allows for more precise calculations and discussions of speed related to navigational charts and maritime routes.

In contrast, the other terms do not directly pertain to speed at sea. "Knob" refers to a rounded handle or control, "measure" is a general term related to determining dimensions or quantities, and "speed" on its own lacks the specific nautical context that "knot" provides. Thus, "knot" is the appropriate and recognized term for maritime speed measurement.