I. ˈləl transitive verb
Etymology: Middle English; probably of imitative origin
Date: 14th century
1. : to cause to sleep or rest : soothe
2. : to cause to relax vigilance
were lull ed into a false sense of security
II. noun
Date: 1719
1. archaic : something that lulls ; especially : lullaby
2. : a temporary pause or decline in activity
the early-morning lull in urban noise
as
a. : a temporary calm before or during a storm
b. : a temporary drop in business activity