Fusion, or synthesis, is the process of combining two or more distinct entities into a new whole.

Fusion may also refer to:

• Nuclear fusion, multiple atomic nuclei combining to form one or more different atomic nuclei and subatomic particles
  • Fusion power, power generation using controlled nuclear fusion reactions
  • Cold fusion, a hypothesized type of nuclear reaction that would occur at or near room temperature
• Heat fusion, a welding process for joining two pieces of a thermoplastic material
• Melting, or transitioning from solid to liquid form

• Binaural fusion, the cognitive process of combining the auditory information received by both ears
• Binocular fusion, the cognitive process in binocular vision of combining the visual information received by both eyes
• Cell fusion, a process in which several uninuclear cells combine to form a multinuclear cell
• Gene fusion, a genetic event and molecular biology technique
• Lipid bilayer fusion, a part of several cellular processes
• Spinal fusion, a surgical technique used to combine two or more vertebrae
• Tooth fusion, a dental abnormality in which two teeth are joined

• Image fusion, a process of combining relevant information from two or more images into a single image
• Loop fusion, a compiler program-optimization transformation that replaces multiple loops with a single one
• Sensor fusion, the combining of sensory data from disparate sources

• Autodesk Fusion, a product development CAD, CAM and CAE program by Autodesk (formerly Fusion 360)
• Blackmagic Fusion, a visual effects package
• BT Fusion, a defunct UK voice-over-IP service
• Lucidworks Fusion, a search engine platform
• NetObjects Fusion, a web design program

• Compiz Fusion, a community-maintained set of plugins for the Compiz Window Manager
• IBRIX Fusion, a parallel file system
• Oracle Fusion Middleware, a portfolio of standards-based software products that spans multiple services
• VMware Fusion, a virtual machine software product

• Fusion (Eclipse Comics)
• Fusion (Marvel Comics), the name of two supervillains
• Fusion (Marvel/Top Cow), a crossover between Marvel and Top Cow Productions

• "Fusion" (Star Trek: Enterprise), a first-season episode of Star Trek: Enterprise
• Fusion (TV channel), an American cable and satellite news channel

• Dancing Stage Fusion, a 2004 music video game by Konami
• Fuzion, a merger of Interlock System and Hero System
• Metroid Fusion, a 2002 Game Boy Advance game
• Philadelphia Fusion, a E-sports gaming team
• Fusion (video game), 1988

• Fusion (Kent State University)
• Fusion (music magazine), an American music magazine, 1967 to 1974
• Fusion Magazine (political magazine), founded and edited by Glenn Beck
• Fusion Magazine (scientific magazine), predecessor to 21st Century Science and Technology magazine

• Jazz fusion, genre that combines rock and jazz, starting in 1960s
• Fusion dance, a type of partner dance that combines two or more dance styles
• Fusion (Jimmy Giuffre 3 album), 1961
• Fusion (Jeremy Steig album), 1972
• Fusion (Sawthis album), 2006
• Fusion Festival, a music festival in Lärz, Germany
• Guardian (band), a Christian rock band formerly called Fusion
• Fusion, a British band whose members included Nik Kershaw and Reg Webb

• Fusion Party, a name for multiple political parties in American history
• Fusion Party (Australia)
• Fusion Energy Foundation, a defunct American non-profit think tank co-founded by Lyndon LaRouche in 1974
• Fusion International, an Australian-based Christian organisation
• Fusion of Haitian Social Democrats, a Haitian political party
• Fusion – Sarvodaya ICT4D Movement, Information and Communications Technology for Development, Sri Lanka

• Cleveland Fusion, a women's American football team in the NWFA
• Fort Wayne Fusion, Arena football team
• Miami Fusion, a professional soccer club in Fort Lauderdale
• Philadelphia Fusion, an American esports team

• Fusion Academy, a private alternative school in several U.S. cities
• Fusion Media Group, a division of Univision Communications

• Fusion of powers, a feature of some parliamentary forms of government
• Fusionism (politics), the combination of libertarianism and various types of conservatism
• Electoral fusion, an arrangement where two or more political parties support a common candidate
• Fusion of law and equity, combining the rules of equity and common law into one set of rules
• Fusion of the legal profession, the elimination of the distinction between barristers and solicitors

• AMD Fusion, a combined microprocessor and GPU design, now branded as AMD Accelerated Processing Unit
• Ford Fusion (Americas), a mid-sized car produced by Ford Motor Company
• Ford Fusion (Europe), a mini MPV produced by Ford Motor Company
• Schumacher Fusion, a radio-controlled car
• Gillette Fusion, a safety razor by Gillette
• Fusion, a brand name of computer hardware used by Arctic

• Fusion (phonetics), the merger of phonological features of two speech segments into one feature
• Fusion cuisine, the combination of elements of various culinary traditions
• Fusional language or inflected language, a type of language
• Information fusion, the merging of information from disparate sources

• Fuse (disambiguation)
• Fusing (disambiguation)
• Cold fusion (disambiguation)
• Fission (disambiguation), opposite of fusion