in a general sense, denotes the lowest part of a thing, in contradistinction to the top or uppermost part.

Navigation, is used to denote as well the channel of rivers and harbours, as the body or hull of a ship. Thus, in the former sense, we say, *gravely bottom*, *clayey bottom*, *sandy bottom*, and so forth; in the latter, a *British bottom*, a *Dutch bottom*, and the like.