A second is directly part of other units, such as frequency measured in hertz (inverse seconds or s −1), speed in meters per second, and acceleration in meters per second squared.

The meaning of SECOND is next to the first in place or time. How to use second in a sentence.

SECOND definition: 1. immediately after the first and before any others: 2. the position in which a person finishes a…. Learn more.

SECOND definition: the sixtieth part of a minute of time. See examples of second used in a sentence.

A second is a unit of time, and one of the sixty parts that a minute is divided into.

1. In the second order, place, or rank: finished second. 2. But for one other; save one: the second highest peak.

Oct 15, 2025 · second, fundamental unit of time, now defined in terms of the radiation frequency at which atoms of the element cesium change from one state to another.