Definition

1. Noun:
   • The International System of Units: A globally accepted, coherent system of measurement units based on seven defining constants. It provides a standardized framework for scientific and technical communication worldwide.

Usage

The term "SI unit" is used to refer to any specific unit within this system or to the system as a whole. It is a standard term in scientific, engineering, and technical contexts. * The meter is the SI unit for length. * All measurements in the experiment were recorded in SI units. * Converting to SI units simplifies international collaboration.

Examples

• The kilogram is the SI unit of mass, though its definition is now based on a fundamental physical constant.
• When writing a scientific paper, you must express your results using SI units.
• The ampere, the SI unit of electric current, is one of the seven base units.

Advanced Usage

• Derived SI unit: A unit formed by combining the base SI units according to algebraic relations. For example, the newton (unit of force) is a derived SI unit equal to kg·m/s².
• SI prefix: A prefix like (10³), (10⁻²), or (10⁶) that can be attached to an SI unit to form decimal multiples or submultiples (e.g., kilometer, centigram).

Variants and Related Words

• Metric system: A broader decimal system of measurement of which the SI is the modern, standardized form.
• Base unit: One of the seven fundamental SI units (meter, kilogram, second, ampere, kelvin, mole, candela) from which all other SI units are derived.
• Système International d'Unités: The full French name, which is the source of the abbreviation "SI".

Synonyms

• International System of Units
• Metric system (in its modern, standardized form)

Related Phrases

• SI base unit: Specifically refers to one of the seven fundamental units of the system.
• SI derived unit: Refers to a unit defined as a product of powers of the base units.

Noun

1. a complete metric system of units of measurement for scientists; fundamental quantities are length (meter) and mass (kilogram) and time (second) and electric current (ampere) and temperature (kelvin) and amount of matter (mole) and luminous intensity (candela)
   • Today the United States is the only country in the world not totally committed to the Systeme International d'Unites