What is the meaning of the word "second"?

Definitions:

A musical interval or tone that is two diatonic scale degrees above or below a given tone. NOUN
- The melody moves up by a second in the next measure.
A person who supports or assists another, especially in a debate or duel. NOUN
- He served as the second to the duelist, ensuring fair play.
A unit of time equal to one sixtieth of a minute. NOUN
- There are 60 seconds in a minute.
Additional to that already existing, used, or possessed. ADJECTIVE
- They have a second home in Europe.
Coming next after the first in order, place, rank, or time. ADJECTIVE
- She was the second person to arrive at the party.
The gear that has the second lowest forward gear ratio in the gear box of a motor vehicle. NOUN
- He had to shift down into second to make the hill.
The position following the first in a sequence; one coming after another. NOUN
- She finished in second place in the race.
To formally endorse or support a proposal or motion in a meeting. VERB
- I second the motion to adjourn the meeting.