Natant

a. [ L. natans, -antis, from swim, v. intens. fr. nare to swim: cf. F. natant. ] 1. (Bot.) Floating in water, as the leaves of water lilies, or submersed, as those of many aquatic plants. [ 1913 Webster ]

2. (Her.) Placed horizontally across the field, as if swimming toward the dexter side; said of all sorts of fishes except the flying fish. [ 1913 Webster ]