The Collaborative International Dictionary
Cobwork
Cobwork \Cob"work`\, a. Built of logs, etc., laid horizontally, with the ends dovetailed together at the corners, as in a log house; in marine work, often surrounding a central space filled with stones; as, a cobwork dock or breakwater.
Wiktionary
cobwork
n. construction work made of logs, etc., laid horizontally, with the ends dovetailed together at the corners, and in marine work often surrounding a central space filled with stones