- Gr. Myth. the nine-headed serpent slain by Hercules as one of his twelve labors: when any one of its heads is cut off, it is replaced by two others
- a long S constellation between Cancer and Libra: the largest constellation
- any persistent or ever-increasing evil with many sources and causes
- any of a family (Hydridae) of small, freshwater, solitary hydroids having a dominant soft-bodied polyp stage
Origin of HydraMiddle English ydre (; from Old French ; from L), ydra ; from Classical Latin Hydra ; from Gr, water serpent, akin to hyd?r, water
nounpl. hy·dras or hy·drae
Origin of hydraNew Latin Hydra, genus name, from Latin Hydra, Hydra; see Hydra.
detail of a late 6th-century bc black-figure amphora depicting Hercules slaying the Hydra of Lerna
- Greek Mythology The many-headed monster that was slain by Hercules.
- Astronomy A satellite of Pluto.
- A constellation in the equatorial region of the southern sky near Cancer, Libra, and Centaurus. Also called Snake2.
- A persistent or multifaceted problem that cannot be eradicated by a single effort.
Origin of HydraMiddle English Idra, from Latin Hydra, from Greek Hudra, Hydra, a water serpent; see wed-1 in Indo-European roots.
(plural hydras or hydrae or hydræ)
After the Hydra, from Greek mythology, which grew two new heads every time one of its heads was cut off. The first sense alludes to the budding method of asexual reproduction that the hydra practices, similar to growing new heads. The second sense refers to how the creature could not be killed by a swift, decisive solution (in contrast to a Gordian knot).
- (Greek mythology) A mythological serpent with seven heads, slain by Hercules as one of his twelve labours. Also called the Lernaean Hydra.
- (astronomy) A spring constellation of the northern sky, said to resemble a serpent. It lies just south of the zodiac and contains the star Alphard.
- (astronomy) The name of one of Pluto's moons. (Named 21 June 2006).
hydra - Computer Definition
(1) A secure Web server from Sentinel Systems, formerly Bodacion Technologies, Barrington, IL (www.bodacion.com). Sentinel is a wholly owned company of the Centuria Corporation, www.centuria.us. HYDRA is a virus-proof, hacker-proof PowerPC-based system that uses a proprietary operating system kernel for running Java servlets and JSPs. Applications programmed in the company's own Genesis language can be compiled on Windows and Unix workstations and then uploaded. As an extra step in foiling hackers who insert bogus packets into the data stream, HYDRA includes software that generates extremely random numbers called "Bodacions." Applications can use Bodacions to generate numbers such as account numbers, session IDs and TCP sequence numbers.
(2) (Hydra) The code name for Windows Terminal Server. See Windows Terminal Server.
(3) (HYbrid Document Reproduction Apparatus) A printer, photocopier, scanner and fax built into one machine.
(4) (Hydra) A device that converts analog signals to ISDN Basic Rate Interface (BRI).