Unit:

Units are standard quantities used to express and measure physical quantities in a consistent way. Without units, a numerical value has no meaning in science. For example, saying “5” is incomplete, but “5 meters” clearly indicates a measurement of length.

Measurement:

Measurement is the process of comparing an unknown physical quantity with a known standard unit to determine its value. It involves both a numerical value and a unit, making the result meaningful and usable in calculations.