Rode is the nautical term for an anchor line, regardless of whether is it a chain or nylon line. The term rode is used for both regular anchors and sea anchors. Rode was originally an Americanism, and may not be used in all English speaking areas of the world.
The length of the rode that is let out is referred to as its scope; the appropriate scope is usually calculated as a ratio of the length of rode to the water depth (usually at least 3:1), or in the case of sea anchors, the length of the rode to the length of the boat (usually at least 10:1 in storm conditions).
Rodes of chain are stronger and require less scope, allowing you to anchor in a tighter area. Any slack may embed itself into the mud, essentially giving you a bit of extra anchor. However, the added weight and the need for a winch if anchoring in deep waters make chain rodes impractical for smaller craft. For this reason, nylon rodes are popular, but usually have a short length of chain between the anchor and the nylon to help set the anchor. Nylon rodes are also more elastic, lessening shock loads. Nylon rodes are almost always used for sea anchors.
The anchor, rode, and any equipment used to set and retrieve the anchor are collectively known as the ground tackle.