By or BY may refer to:
The Byzantine Empire, also referred to as the Eastern Roman Empire and Byzantium, was the continuation of the Roman Empire in the East during Late Antiquity and the Middle Ages, when its capital city was Constantinople (modern-day Istanbul, which had been founded as Byzantium).
Byun Baek-hyun (born May 6, 1992), better known mononymously as Baekhyun, is a South Korean singer, songwriter, actor, model and fashion designer.
The bystander effect, or bystander apathy, is a social psychological phenomenon in which individuals are less likely to offer help to a victim when other people are present.
The Byelorussian Soviet Socialist Republic (BSSR, or Byelorussian SSR; Belarusian: Беларуская Савецкая Сацыялiстычная Рэспублiка, translit.
The Byzantine Rite, also known as the Greek Rite or Constantinopolitan Rite, is the liturgical rite used by the Eastern Orthodox Church as well as by certain Eastern Catholic Churches; also, parts of it are employed by, as detailed below, other denominations.
Bydgoszcz (Polish: [ˈbɨdɡɔʂt͡ʂ] ( listen); German: Bromberg [ˈbʁɔmbɛɐ̯k]; Latin: Bydgostia) is a city in northern Poland, on the Brda and Vistula rivers.
Bye Bye Birdie is a stage musical based on a book by Michael Stewart, with lyrics by Lee Adams and music by Charles Strouse.
BYD Auto Co., Ltd. is a Chinese automobile manufacturer based in Xi'an, Shaanxi Province, and a wholly owned subsidiary of BYD Company.