TIL a second is called a second because it is the second division of the hour by 60, the first being a minute.

Where did a second come from?

Seconds were once derived by dividing astronomical events into smaller parts, with the International System of Units (SI) at one time defining the second as a fraction of the mean solar day and later relating it to the tropical year.

Why are second and second the same word?

Basically, you divide an hour into smaller units once, call them minutes, and divide those again (the second division) and calls those seconds.