(informal) The belief that food dropped on the ground may safely be eaten provided it is picked up within five seconds of touching the ground.

(slang, US) A thief, especially one who climbs into buildings above ground level.

plural of second-level domain

(transport, idiomatic) A rule of thumb for safe driving by which a driver must maintain a two-second distance from the vehicle in front.

plural of error of the second kind

(statistics) type II error

second-degree murder

plural of second-person plural

a rule of thumb by which a driver may maintain a safe following distance, allowing at least a two second interval behind any vehicle that is directly in front of the driver's vehicle.

plural of second-person singular