A Grism (GRating+prISM) is an optical prism which has a transmission grating fabricated onto one (rarely two) of its plane (rarely curved) functional surfaces. Grisms have a straight view or undeviated wavelength. This property allows them to transform a camera into a spectrograph by inserting the grism in the optical beam path. This can be used in various applications, e.g. astronomy. By selecting the groove density and the apex angle of the prism accordingly, the straight view wavelength and the angular dispersion of the grism can be adapted to the needs of the specific application.