A cloud type the elements of which have the form of more or less isolated, generally smooth lenses or almonds, with sharp outlines. Orographically formed, the result of lee waves, they remain nearly stationary with respect to the terrain; but also occur in regions without marked orography.

(lentil): Clouds having the shape of lenses or almonds, often very elongated and usually with well-defined outlines; they occasionally show irisation. Such clouds appear most often in cloud formations of orographic origin, but may also occur in regions without marked orography.