Hy"dro*plane (?), n. [Pref. hydro- , 1 + plane.] 1. A plane, or any of a number of planes, projecting from the hull of a submarine boat, which by being elevated or depressed cause the boat, when going ahead, to sink or rise, after the manner of an aëroplane.

2. A projecting plane or fin on a gliding boat to lift the moving boat on top of the water; also, a gliding boat.

Hy"dro*plane, v. i. Of a boat, to plane (see Plane, below).

Hy"dro*plane (?), n. [Pref. hydro- , 1 + plane.] 1. A plane, or any of a number of planes, projecting from the hull of a submarine boat, which by being elevated or depressed cause the boat, when going ahead, to sink or rise, after the manner of an aëroplane.

2. A projecting plane or fin on a gliding boat to lift the moving boat on top of the water; also, a gliding boat.

Hy"dro*plane, v. i. Of a boat, to plane (see Plane, below).