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 implementatio ...

* Hydra (operating system) *

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 HYDRA Engine is a brand name for a multi-Graphical Processing Unit, GPU developed by Lucid Logix. Similar to nVidia's Scalable Link Interface, SLI and ATI Technologies, ATI's ATI CrossFire, Crossfire-technologies, Hydra allows linking several video ...

, 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 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'' * "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, Greek frigate ''Hydra'', a ''MEKO 200''-type frigate launched in 1992, lead ship of the ''Hydra'' class frigate * HMS Hydra (1797), HMS ''Hydra'' (1797), a 38-gun fifth rate * HMS Hydra (1838), HMS ''Hydra'' (1838), a wooden steam paddle sloop ** Hydra-class sloop, ''Hydra''-class sloop, a class of British steam sloops * HMS Hydra (1871), HMS ''Hydra'' (1871), a Cyclops-class turret ship * HMS Hydra (1912), HMS ''Hydra'' (1912), an Acheron-class destroyer * HMS Hydra (J275), HMS ''Hydra'' J275), an Algerine-class minesweeper launched in 1942 * HMS Hydra (A144), HMS ''Hydra'' (A144), an oceanographic survey vessel launched in 1965 * Hydra-class minelayer, a class of Dutch 1910s minelayers

Other uses

* ''The Hydra'', a literary magazine * Hydra (association), a German self-help and advocacy group for prostitutes * Hydra (video game), ''Hydra'' (video game), an arcade and Atari Lynx video game * Hydra game, a concept in mathematical logic * Hydra Market, a Russian language dark web marketplace that facilitated trafficking of illegal drugs as well as financial services * Hydra the Revenge, a roller coaster at Dorney Park in Pennsylvania, US * Hydra 70, an air-to-ground rocket * Hydra Technologies, an unmanned aerial vehicle firm * Hydra Trophy, a trophy of the roller derby WFTDA Championships * Hydra, a wireless station during World War II at Camp X#Hydra, Camp X * Operation Hydra (Yugoslavia) * Operation Hydra (1943)