A second is a very short time. It is one sixtieth of a minute. We use it to measure how long things take.
Wait for five seconds, please.
The race was over in ten seconds.
Second means the place after first. In sports or contests, it means the person who comes next to the winner.
She finished second in the race.
He came second in the competition.
Second is used to show order. It means something comes after the first one in a list or time.
This is the second book I read.
She took the second bus home.
To second something means to say you agree with a proposal, especially in formal meetings. It helps the group make a decision.
I second the motion to start now.
She seconded his idea in the meeting.
Second can mean a very small unit to measure angles. It is one sixtieth of a minute of angle, used by scientists and astronomers.
The star moved by two seconds of arc.
Measure the angle in seconds.
Second can mean a helper in a duel or a person’s next spouse after divorce or death. These uses are formal or old-fashioned.
His second helped prepare for the duel.
She was his second wife.
Second as a verb means to support an idea in a meeting or group. It shows you agree and want others to consider it.
I second your suggestion.
Can you second his motion?