turi-ye narde-yi (#)
Fr.: réseau à échelle
A diffraction grating in which the groves are relatively widely spaced and serves to provide high resolution and dispersion.
Echelle, from Fr. échelle "ladder," , from O.Fr. eschele, from L. scala "ladder;" → grating.
Turi, → grating; nardé, contraction of nardebân "ladder; échelle."