Short for nonsynchronous or nonsynchronized. <span class="searchmatch">nonsync</span> (not comparable) (film) Relating to a soundtrack that is not synchronized with the picture, but played...
Movies Without Shooting Yourself in the Foot, page 216: If you don't mind windup, spring-driven cameras, the Bolex 16s are good <span class="searchmatch">nonsync</span> cameras. upwind...