Question: A unit of time or time unit is any particular time interval, used as a standard way of measuring or expressing duration, the exact modern definition, is from the National Institute of Standards and Technology (NIST), a measurement standards laboratory, and a non-regulatory agency of which organization?
Sentence (from "Unit of time"): A unit of time or time unit is any particular time interval, used as a standard way of measuring or expressing duration.
Relevant evidence: No