D defs.my
Entry 1 sense Webster, 1913

Water ballast

/wôt'-ẽr băl'-əst/ · Wa·ter bal·last · IPA
01 Water confined in specially constructed compartments in a vessel's hold, to serve as ballast.
  1. 1.
    Water confined in specially constructed compartments in a vessel's hold, to serve as ballast.(Naut.)