from
The Collaborative International Dictionary of English v.0.48
Louver \Lou"ver\, Louvre \Lou"vre\, n. [OE. lover, OF. lover,
lovier; or l'ouvert the opening, fr. overt, ouvert, p. p. of
ovrir, ouvrir, to open, F. ouvrir. Cf. {Overt}.] (Arch.)
A small lantern. See {Lantern}, 2
(a) . [Written also {lover}, {loover}, {lovery}, and
{luffer}.]
2. Same as {louver boards}, below
[PJC]
3. A set of slats resembling louver boards, arranged in a
vertical row and attached at each slat end to a frame
inserted in or part of a door or window; the slats may be
made of wood, plastic, or metal, and the angle of
inclination of the slats may be adjustable simultaneously,
to allow more or less light or air into the enclosure.
[PJC]
{Louver boards} or {Louver boarding}, the sloping boards set
to shed rainwater outward in openings which are to be left
otherwise unfilled; as belfry windows, the openings of a
louver, etc.
{Louver work}, slatted work.