an epithet usually applied by sailors to whatever is principal, as opposed to whatever is inferior or secondary. Thus the main land is used in contradistinction to an island or peninsula; and the mainmast, the main-wale, the main-keel, and the main-hatchway, are in like manner distinguished from the fore and mizen masts, the channel-wales, the false keel, and the fore and after hatchways, &c.