jungle

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Land covered with a dense growth of tropical vegetation.
• noun A dense thicket or growth.
• noun A dense, confused mass; a jumble.
• noun Something made up of many confused elements; a bewildering complex or maze.
• noun A place or milieu characterized by intense, often ruthless competition or struggle for survival.
• noun Slang A place where hoboes camp.

from The Century Dictionary.

• noun A dense growth of rank and tangled vegetation, large and small, often nearly impenetrable, such as is characteristic of some parts of India, especially in the swampy regions at the base of the Himalaya mountains.
• noun A tract of land covered by such vegetation; a wilderness of dense overgrowth; a piece of swampy thickset forest-land.

from the GNU version of the Collaborative International Dictionary of English.

• noun A dense growth of brushwood, grasses, reeds, vines, etc.; an almost impenetrable thicket of trees, canes, and reedy vegetation, as in India, Africa, Australia, and Brazil.
• noun A place of danger or ruthless competition for survival.
• noun Anything which causes confusion or difficulty due to intricacy.
• noun (Zoöl.) the aswail or sloth bear.
• noun (Zoöl.) the chaus.
• noun (Zoöl.) the male of a jungle fowl.
• noun (Zoöl.) An Australian grallatorial bird (Megapodius tumulus) which is allied to the brush turkey, and, like the latter, lays its eggs in mounds of vegetable matter, where they are hatched by the heat produced by decomposition.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A large, undeveloped, humid forest, especially in a tropical region, that is home to many wild plants and animals.
• noun colloquial A place where people behave ruthlessly, unconstrained by law or morality.
• noun slang An area where hobos camp together.
• noun uncountable A style of electronic music related to drum and bass.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an impenetrable equatorial forest
• noun a place where hoboes camp
• noun a location marked by an intense competition and struggle for survival