Time

1. Time is a scalar quantity (often denoted by the symbol t) and, like length, mass, and charge, is usually described as a fundamental quantity.
2. Time – the basic concept of the human mind, showing the variability of the world, procedural nature of its existence, the existence of the world is not just «things» (objects, objects), but also events.

In the International System of Units (SI), the unit of time is the second (symbol: s ). It is a SI base unit, and 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 atom". This definition is based on the operation of a caesium atomic clock. These clocks became practical for use as primary reference standards after about 1955, and have been in use ever since.

Sources:

Англійський словник Коллінза, https://www.collinsdictionary.com/

Прикладна фізика. Українсько-російсько-англійський тлумачний словник: У 4 т., Т. 4: С — Я / уклад.: О. Т. Богорош, С. О. Воронов, О. Г. Шайко-Шайковський, В. З. Маїк, М. Ф. Ясінський. — Львів : Укр. акад. друкарства, 2015. 882c.

Khan Academy https://www.khanacademy.org/science/physics/