BI, Bi or bi may refer to:

Binomial nomenclature (also called binominal nomenclature or binary nomenclature) is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages.

Bitcoin is a worldwide cryptocurrency and digital payment system called the first decentralized digital currency, as the system works without a central repository or single administrator.

William Henry Gates III (born October 28, 1955) is an American business magnate, investor, author, philanthropist, and co-founder of the Microsoft Corporation along with Paul Allen.

William Jefferson Clinton (born William Jefferson Blythe III; August 19, 1946) is an American politician who served as the 42nd President of the United States from 1993 to 2001. Prior to the presidency, he was the Governor of Arkansas from 1979 to 1981, and again from 1983 to 1992. A member of the Democratic Party, Clinton was ideologically a New Democrat and many of his policies reflected a centrist "Third Way" political philosophy.

The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution.

Birmingham ( ( listen), locally /ˈbɜːmɪŋ(g)əm/) is a city and metropolitan borough in the West Midlands, England standing on the small River Rea.

Big O notation is a mathematical notation that describes the limiting behavior of a function when the argument tends towards a particular value or infinity.

The Big Five personality traits, also known as the five factor model (FFM), is a model based on common language descriptors of personality.

In mathematics and digital electronics, a binary number is a number expressed in the base-2 numeral system or binary numeral system, which uses only two symbols: typically 0 (zero) and 1 (one).