Pronunciation: (bakt),[key] —adj. 1. having a back, backing, setting, or support (often used in combination): a low-backed sofa. 2. (of fabric) having an extra set of threads in either the warp or the weft to provide added warmth. Cf. double cloth. 3. Photog.(of a film or plate) coated with a substance for absorbing light and thereby reducing halation.