A nuclear-equipped walking battle tank also equipped with state-of-the-art conventional weaponry such as missiles, heavy machine guns, and lasers. It's main selling point was its ability to launch a variety of nuclear warheads toward anywhere on Earth from any location. It had the ability to more independently and instead of using a standard nuclear launch module, it was equipped with a weapon, which allowed it to launch a nuclear weapon with no external support. Since it could operate from regions, which were up to that point not on the world's nuclear strategy map, it was a weapon that destroyed the sensitive balance of nuclear deterrence and represented an enormous threat to the entire world.
You would really not want to be standing in front of Metal Gear Rex if it had a pilot who was unfriendly towards you....
by Solid Snake June 23, 2004
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*A massive bipedal tank (bipedal, as in, two-legged) equipped with state-of-the-art weapons, and capable of being equipped with a nuclear arsenal. Being bipedal, it is capable of launching a nuclear missile from ANY point on the face of the earth, from mountains to deserts to swamps, ANYWHERE.

*A verb, used to refer to dangerous intelligence-gathering, spying, espionage, etc.
"A Metal Gear would be cool in real-life, but imagine the dangers..."
-me

"I'm going to Metal Gear that guy's house."
"I'm going to Metal Gear the enemy base."
"That guy can pull off a Metal Gear with ease. ^_^ "
by Dave April 16, 2004
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A term used to describe how large a mans penis is.
Girl: Wow you have some big metal gear!

Boy: thanks!
by Mr.Terry July 11, 2008
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1. Popular video game.

2. Used as a mocking expression (spoken in a rough manly voice) when someone repeats what another person just said as a question (Much like solid snake does in the metal gear series).
Person #1
"It's called Metal Gear"

Snake:
"Metal Gear?"

or

Person #1
"Hey look, a Plane"

Person #2:
"A Plane?"

Person #1:
"Metal Gear?"
by Maul May 6, 2005
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A nuclear equipped walking battle tank. Metal Gear Rex was held by the army, with legendary technology. The US marines later made use of Metal Gear Ray, which was amphibious, unlike the army's Rex. Metal Gear Arsenal was disguised as a rig in the middle of a lotta water. It was revealed to be more than just a weapon, containing nearly every piece of valuable information to the US government. It wasn't just a weapon, but the core of the country. It was guarded by a bunch of Rays. I don't know where the story goes from there, as I have not gotten Metal Gear Solid 3 yet.
Wow. It's a cool name that has been re-used for projects of killing machines and databases for the US government.
by blah December 26, 2005
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