In classical, non-relativistic physics, time is a scalar quantity

Time is a fundamental concept in physics. In classical, non-relativistic physics, time is a scalar quantity (often denoted by the symbol $t$) and is usually described as a fundamental quantity ¹. In physics, time is defined by its measurement: time is what a clock reads ¹. Time can be combined mathematically with other physical quantities to derive other concepts such as motion, kinetic energy, and time-dependent fields ¹.

The unit of measurement of time is the second (symbol: s) in the International System of Units (SI) ¹. It has been defined since 1967 as “the duration of 9,192,631,770 [cycles] of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atoms” ¹. This definition is based on the operation of a caesium atomic clock ¹.

Dr Houston

(1) Time in physics – Wikipedia. https://en.wikipedia.org/wiki/Time_in_physics.
(2) 2.3: Time, Velocity, and Speed – Physics LibreTexts. https://phys.libretexts.org/Bookshelves/College_Physics/College_Physics_1e_%28OpenStax%29/02%3A_Kinematics/2.03%3A_Time_Velocity_and_Speed.
(3) What Is Time? A Simple Explanation – ThoughtCo. https://www.thoughtco.com/what-is-time-4156799.
(4) Does Time Exist? A Physicist’s Perspective – ThoughtCo. https://www.thoughtco.com/does-time-really-exist-2699430.