• Duplicate (film), a Bollywood film directed by Mahesh Bhatt
• Duplicates (film), a 1992 TV-Movie starring Gregory Harrison and Kim Greist
• The Duplicate, a children's book by William Sleater
• Duplicate Boy, a DC comics superhero
• Batman Duplicate, a villain in Batman: The Animated Series
• The Duplicate Man, an episode of The Outer Limits
• The duplicator machine in Calvin and HobbesBiology and genetics
• Gene duplication, a process which can result in free mutation
• Chromosomal duplication, which can cause Bloom and Rett syndrome
• Polyploidy, a phenomenon also known as ancient genome duplication
• Enteric duplication cysts, certain portions of the gastrointenstinal tract
• Diprosopus, a form of cojoined twins also known as craniofacial duplication
• Diphallia, a medical condition also known as penile duplicationComputing
• Duplicate code, a source code sequence that occurs more than once in a program
• Duplicate characters in UnicodeMathematics
• Duplication matrix, a linear transformation dealing with half-vectorization
• Doubling the cube, a problem in geometry also known as duplication of the cube
• A type of multiplication theorem called the Legendre duplication formula or simply "duplication formula"Technology
• Duplicating machines, machines and processes designed to reproduce printed material, photocopying being among the best-known today; see also List of duplicating processes
• Loop bin duplicator, a device designed to copy pre-recorded audio tapes
• Double track, a method of railway design also known as track duplication
• In road construction, conversion of a single carriageway into Dual carriagewayOther
• Duplicate publication, the publication same intellectual material by the same author twice
• Reduplication, a morphological process in linguistics
• Rebirthing (Breathwork) duplicate, a therapeutic technique in alternative medicine
• Duplicate bridge, a popular variant of contract bridge, and its variant Duplicate Tsing Yi South Bridge
• Duplicate Scrabble, a Scrabble variant popular in French and some other languages.
• "Decouple, duplicate, discriminate," the "three Ds" articulated by Madeleine Albright as necessary for NATO to avoid

See also

• Clone
• Congruence
• Copy
• Doppelgänger
• Double
• Plagiarism
• Reproduction (disambiguation)
• Reproducibility
• Replication
• Repetition
• Redundancy
• Symmetry