A centimeter is about the width of a fingernail
The estimating unit of measure for the width of a fingernail is typically in millimeters (mm) or centimeters (cm). Some may also use inches (in) as a measurement unit, but millimeters are the most commonly used unit for the width of a fingernail.
Millimetres.
The metric unit used for measuring the width of a fingernail is usually millimeters (mm).
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The width of a fingernail is typically around 1 to 2 millimeters.
about 1 centimeter
about the width of the tip of your fore finger, depending on how wide your fingers are.
centimeters
Millimeters
Mm
appropriate unit to measure the width of a textbook = ce ntimeters
It is any linear unit you want to use, depending on the magnitude of the width and on your particular requirements.