I. lag 1 /læɡ/ BrE AmE verb ( past tense and past participle lagged , present participle lagging )
[ Date: 1500-1600 ; Origin: Probably from a Scandinavian language ]
1 . [intransitive and transitive] to move or develop more slowly than others
lag behind
She stopped to wait for Ian who was lagging behind.
Britain is lagging behind the rest of Europe.
2 . [transitive] British English to cover water pipes etc with a special material to prevent the water inside them from freezing or the heat from being lost:
We’ve had the hot-water tank lagged.
II. lag 2 BrE AmE noun [countable]
a delay or period of waiting between one event and a second event:
a time lag
⇨ ↑ jet lag , ↑ old lag