Hydra generally refers to: * Lernaean Hydra, a many-headed serpent in Greek mythology * ''Hydra'' (genus), a genus of simple freshwater animals belonging to the phylum Cnidaria Hydra or The Hydra may also refer to:

Astronomy

* Hydra (constellation) * Hydra (moon), a satellite of Pluto

Computing

* Hydra (chess), a chess computer *

Hydra (digital repository) Samvera, originally known as Hydra, is an open-source digital repository software product. Samvera main components are Fedora Commons, Solr, Blacklight, and HydraHead (a Ruby on Rails plugin and gem, respectively). Each Samvera implementation is ...

Hydra (operating system) Hydra (stylized as HYDRA) is an early, discontinued, Capability-based security, capability-based, Object-oriented programming, object-oriented microkernel designed to support a wide range of possible operating systems to run on it.Wulf 74 pp. 337� ...

Hydra (software) Hydra (or THC Hydra) is a parallelized network login cracker built in various operating systems like Kali Linux, Parrot and other major penetration testing environments. Hydra works by using different approaches to perform brute-force attacks in ...

* Hydra 100, a multi-GPU hardware solution * HYDRA Game Development Kit, a development system by André LaMothe * Razer Hydra, a game controller *

NEC HYDRAstor NEC HYDRAstor is a disk-based grid storage system with data deduplication for backups and archiving, developed by NEC Corporation. A HYDRAstor storage system can be composed of multiple nodes, starting from one up to 100+ nodes. Each node contains ...

, a storage system

Fictional entities

* Hydra (comics), a fictional organization in the Marvel Universe ** Hydra (Marvel Cinematic Universe), an organisation in the Marvel Cinematic Universe based on the comics counterpart * Hydra (''Dungeons & Dragons''), a fictional monster in ''D&D'' * Hydra (''Transformers''), a character in ''Transformers'' * The Hydra, a fictional organization in '' The Phantom'' * Hydra, a character in '' UFO Ultramaiden Valkyrie'' * The Hydra, a fictional deity created by Henry Kuttner ** Mother Hydra, the co-ruler of the Deep One race in the Cthulhu Mythos * The Hydra, a fictional fighter jet in '' Grand Theft Auto: San Andreas'' and ''Grand Theft Auto Online'' * The Hydra, a fictional machine in '' Kirby Air Ride''

Film and television

* '' Hydra'' (film), a 2008 monster movie * Hydra (''Chuck''), a fictional database on ''Chuck'' * Hydra, a fictional

Dharma Initiative The Dharma Initiative, also written DHARMA (Department of Heuristics and Research on Material Applications), is a fictional research project and organization featured in the television series ''Lost''. It was introduced in the second season epis ...

station on ''Lost''

Music

* Hydra Entertainment, the hip-hop record label * Hydra (band), an American southern rock band in the 1970s * ''Hydra'' (Otep album), 2013 * Hydra, a 2005 album by Satariel (band) * ''Hydra'' (Toto album),1979, or the title song * ''Hydra'' (Within Temptation album), 2014 * ''Hydra'' (Iris album), a 2008 album by Iris * "Hydra", a 2000 song by Dir En Grey from ''

Macabre In works of art, the adjective macabre ( or ; ) means "having the quality of having a grim or ghastly atmosphere". The macabre works to emphasize the details and symbols of death. The term also refers to works particularly gruesome in natu ...

'' * "Hydra", a song by Twilight Force from the 2019 album '' Dawn of the Dragonstar'' * "HYDRA", a 2018 song by Myth & Roid

People

Hydra (skater) Jennifer Wilson, known as Hydra, is a roller derby skater who has played a leading role in the development of the sport. Hydra joined Bad Girl Good Woman (BGGW) in 2001, around the time that the league was founded.Hydra (wrestler), American professional wrestler

Places

* Hydra, Algeria, a neighbourhood and a municipality in Algiers * Hydra (island), an island of Greece

Ships

* ''Hydra'' (ship), a hydrogen ship * Greek ironclad ''Hydra'', a French-built ironclad warship launched in 1889 * Greek destroyer ''Hydra'', a ''Dardo''-class destroyer launched in 1932 * Greek frigate ''Hydra'', a ''MEKO 200''-type frigate launched in 1992, lead ship of the ''Hydra'' class frigate * HMS ''Hydra'' (1797), a 38-gun fifth rate * HMS ''Hydra'' (1838), a wooden steam paddle sloop ** ''Hydra''-class sloop, a class of British steam sloops * HMS ''Hydra'' (1871), a Cyclops-class turret ship * HMS ''Hydra'' (1912), an Acheron-class destroyer * HMS ''Hydra'' J275), an Algerine-class minesweeper launched in 1942 * HMS ''Hydra'' (A144), an oceanographic survey vessel launched in 1965 *

Hydra-class minelayer The ''Hydra'' class were two minelayers of the Royal Netherlands Navy, built to serve in the Dutch East Indies and Dutch territorial waters in Europe. The construction of the ships began in 1910 and was completed in 1912. The ships were built by ...

, a class of Dutch 1910s minelayers

Other uses

* ''

The Hydra ''The Hydra'' was a magazine produced by the patients of the Craiglockhart War Hospital, noteworthy for having been edited at one time by Wilfred Owen, and for including poems by Siegfried Sassoon. The magazine was headquartered in Edinburgh. ...

'', a literary magazine *

Hydra (association) Hydra e. V. is a German Support group, self-help and advocacy group for prostitutes. The self- proclaimed "Hurenorganisation" (Whore organisation) is a Nonprofit organization, non-profit association that was founded in 1980 by interested women as ...

, a German self-help and advocacy group for prostitutes * ''Hydra'' (video game), an arcade and Atari Lynx video game *

Hydra game In mathematics, specifically in graph theory and number theory, a hydra game is a single-player iterative mathematical game played on a tree (graph theory), mathematical tree called a ''hydra'' where, usually, the goal is to cut off the hydra's "h ...

, a concept in mathematical logic *

Hydra Market Hydra was a Russian language dark web marketplace that facilitated trafficking of illegal drugs as well as financial services including cryptocurrency tumbler, cryptocurrency tumbling for money laundering and exchange services between cryptocurr ...

, a Russian language dark web marketplace that facilitated trafficking of illegal drugs as well as financial services *

Hydra the Revenge Hydra the Revenge (sometimes simply shortened to Hydra) is a steel Floorless Coaster at Dorney Park & Wildwater Kingdom in Allentown, Pennsylvania. It is the only floorless roller coaster in Pennsylvania and was opened on May 7, 2005. Hydra w ...

, a roller coaster at Dorney Park in Pennsylvania, US *

Hydra 70 The Hydra 70 rocket is a diameter fin-stabilized unguided rocket used primarily in the air-to-ground role. It can be equipped with a variety of warheads, and in more recent versions, guidance systems for point attacks. The Hydra is widely used by ...

, an air-to-ground rocket *

Hydra Technologies Hydra Technologies is a Mexican firm dedicated to the design and development of unmanned aerial vehicles for surveillance operations and aircraft avionics. The company has one hundred employees and as of mid-2008 has two operational models, the ...

, an unmanned aerial vehicle firm *

Hydra Trophy The Hydra Trophy is the trophy awarded to the Women's Flat Track Derby Association (WFTDA) team that wins the WFTDA Championship Tournament at the conclusion of every WFTDA roller derby season. Named in honor of Hydra, founding member of the WF ...

, a trophy of the roller derby WFTDA Championships * Hydra, a wireless station during World War II at

Camp X Camp X was the unofficial name of the secret Special Training School No. 103, a Second World War British paramilitary installation for training covert agents in the methods required for success in clandestine operations. It was located on the ...

* Operation Hydra (Yugoslavia) *

Operation Hydra (1943) Operation Hydra was an attack by RAF Bomber Command on a German scientific research centre at Peenemünde on the night of 17/18 August 1943. Group Captain John Searby, commanding officer of No. 83 Squadron RAF, commanded the operation, the ...