Used as a time unit, identical to the English 'second'. Common in technical, sports, and everyday timing contexts.
He ran 100 meters in 11 seconds.
Time's up in 30 seconds.
second (boxing); assistant; trainer
Primarily used in boxing and combat sports for the person who assists a fighter between rounds. Can also refer to a helper or trainer in other sports contexts.
The boxer received advice from his second between rounds.
He acted as a second at the match.