Unit

The word unit can mean more than one thing:

• One, the first natural number.
• The natural or usual or smallest measure of something, of which there are multiples and of which there may be fractions.
• In most physical contexts, 'unit' is used to mean a physical unit.
• A currency is a unit of money (a monetary unit).
• In mathematics, 'unit' often refers to the number one in some sense:
  • A unit vector is a vector with length 1.
  • The unit circle is the cirle with radius 1 centered at the origin of the coordinate system.
  • The unit interval is the interval of all real numbers between 0 and 1.
  • The imaginary unit of complex numbers is the number i, a number whose square is -1.
  • A root of unity is a complex number a power of which is 1.
  • A unit of a ring is an element of the ring that is invertible with respect to the ring multiplication.
• In science and engineering, 'unit' refers to the form of measurement of a quantity. These systems are typically characterized by the units chosen for mass, distance, and time. Unit systems include
  • SI (mks), the most commonly used units worldwide
  • cgs, derived from SI and also commonly used worldwide; also one of two standard unit systems in astronomy
  • mts, little used
  • imperial units (inlbs), also known as British units, were historically used in Britain and are similar (but not identical) to the current day
  • U.S. customary units, primarily used in the USA
• Military units:
  • Unit 101 was an Israeli special operations unit.
  • Unit 731 was a secret military unit of the Japanese army.
• Functional units are components of a system that perform a specific function:
  • The Central processing unit (CPU) is the processor of a computer; Arithmetic and Logical Unit, Control unit, Memory management unit and Floating Point Unit are important components of the CPU.
• A multiple unit is a passenger train whose carriages have their own motors.
• In the science fiction television series, "Doctor Who", the initials UNIT stand for the United Nations Intelligence Taskforce.

This is a disambiguation page; that is, one that points to other pages that might otherwise have the same name. If you followed a link here, you might want to go back and fix that link to point to the appropriate specific page. If you know any more meanings of the term 'unit' you may want to add them to this list.