/læg/ noun an interval of time between two linked happenings O There’s often a long time lag between setting up in business and seeing any results. ¢ jet lag ■ verb 1. to be behind, to fall behind O She was lagging 10m behind the leaders. 2. to cover water pipes to prevent them losing heat or freezing O Make sure your pipes are lagged before the winter. (NOTE: lagging – lagged)