By or BY may refer to:
The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinople (modern Istanbul, formerly Byzantium).
The Byelorussian Soviet Socialist Republic (BSSR, or Byelorussian SSR; Belarusian: Беларуская Савецкая Сацыялістычная Рэспубліка, romanized: Biełaruskaja Savieckaja Sacyjalistyčnaja Respublika; Russian: Белорусская Советская Социалистическая Республика, romanized: Belorusskaya Sovetskaya Sotsialisticheskaya Respublika or Russian: Белорусская ССР, romanized: Belorusskaya SSR), also commonly referred to in English as Byelorussia, was a federal unit of the Soviet Union (USSR).
The bystander effect, or bystander apathy, is a social psychological claim that individuals are less likely to offer help to a victim when other people are present; the greater the number of bystanders, the less likely it is that one of them will help.
Byblos (Greek: Βύβλος), known locally as Jbeil (Arabic: جبيل Jubayl) and in the County of Tripoli as Gibelet, is the largest city in the Mount Lebanon Governorate of Lebanon.
Bydgoszcz (UK: BID-goshtch, US: -gawsh(tch), Polish: [ˈbɨdɡɔʂtʂ] (listen); German: Bromberg [ˈbʁɔmbɛɐ̯k]; Latin: Bydgostia, Brombergum) is a city in northern Poland, on the Brda and Vistula rivers.
The BYU Cougars football team is the college football program representing Brigham Young University (BYU), a private university owned by The Church of Jesus Christ of Latter-day Saints.
The Byzantine Rite, also known as the Greek Rite or Constantinopolitan Rite, is the liturgical rite used by the Eastern Orthodox Church, the Greek Catholic Churches, and in a modified form, Byzantine Rite Lutheranism.
The Byzantine–Sasanian War of 602–628 was the final and most devastating of the series of wars fought between the Byzantine Empire and the Sasanian Empire of Iran.
Bye Bye Birdie is a stage musical with a book by Michael Stewart, lyrics by Lee Adams and music by Charles Strouse.