OP

OP may refer to:of

Arts and entertainment

• One Piece, a Japanese manga and anime
• Opposite prompt, a stage right prompt corner on a theatre stage
• Optimus Prime, a Transformer from the films/comics: Transformers
• Opus number, used to denote one work of musical composition from many
• Original Pronunciation, a term used by linguist David Crystal to define the Early Modern English accent originally used in Shakespeare's works.
• Out of print, a status of a book title at a publishing house

Businesses and organizations

• OP Financial Group, Finnish financial services company
• Oborový podnik ("specialized business"), a bygone Czechoslovakian state designation for a business entity
• Ocean Pacific, a retail clothing company based in California, USA
• Oratory Preparatory School, a Catholic preparatory day school for boys in New Jersey, United States
• Dominican Order (Latin: Ordo Praedicatorum), a catholic religious order

Internet

• Original post or original poster, the first post in or person initiating a new Internet thread
• Internet Relay Chat operator
• Overpowered, in video games, when a particular aspect or character is lacking game balance

Mathematics

• Op (statistics), a symbol used in probability mathematics
• Operator (mathematics), a mapping from one vector space or module to another
• Octagonal prism, a prism formed by square sides and two regular octagons

Other uses

• Observation post, a position from which soldiers can watch enemy movements
• Old Pauline, an ex-pupil of St Paul's School, London; see List of Old Paulines
• Opening or Introduction
• Orange pekoe, a grade of black teas
• Organophosphate, the general name for esters of phosphoric acid
• Surgical operation
• Overall Position, the grade appointed to Queensland high-school graduates

See also

• Op-amp, short for Operational amplifier
• Op-ed, a newspaper opinion piece of a writer unaffiliated with the editorial board
• Operation (disambiguation)
• Operator (disambiguation)
• OPS (disambiguation)
• Op. cit., opere citato, or "in the work cited"
• 0P (disambiguation) ("zero p")