Unit Definition in Science

What is a unit in science?

A yard stick
The meter, yard, inch, and centimeter are all units of length.

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A unit is any standard used for making comparisons in measurements. Unit conversions allow for measurements of a property that have been recorded using different units—for instance, centimeters to inches.


The meter is one standard of length. A liter is a standard of volume. Each of these standards can be used to compare with other measurements made using the same units.