The maintenance of one operation in step with another. Abbreviated as ‘sync’.

A picture record and a sound record are said to be ‘in sync’ when they are placed relative to each other on a release print so that when they are projected the action will coincide precisely with the accompanying sound. When these conditions are not met they are said to be ‘out of sync’.

In video it usually refers to the synchronisation pulses necessary to coordinate the operation of several interconnected video components. When the components are properly synchronised, they are said to be ‘in sync’.

A sync generator is an electronic component that generates sync pulses.