dive

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

• intransitive verb To plunge, especially headfirst, into water.
• intransitive verb To execute a dive in athletic competition.
• intransitive verb To participate in the sport of competitive diving.
• intransitive verb To go toward the bottom of a body of water.
• intransitive verb To engage in the sport of scuba diving.
• intransitive verb To submerge under power. Used of a submarine.
• intransitive verb To fall head down through the air.
• intransitive verb To descend nose down at an acceleration usually exceeding that of free fall. Used of an airplane.
• intransitive verb To engage in the sport of skydiving.
• intransitive verb To drop sharply and rapidly; plummet.
• intransitive verb To rush headlong and vanish into something.
• intransitive verb To plunge one's hand into something.
• intransitive verb To lunge or leap headfirst.
• intransitive verb To plunge into an activity or enterprise with vigor and gusto.
• intransitive verb Sports To exaggerate a fall in an attempt to induce a referee to call a penalty on an opponent.
• intransitive verb To cause (an aircraft, for example) to dive.
• intransitive verb To go scuba-diving to or along.
• noun A plunge into water, especially done headfirst and in a way established for athletic competition.
• noun The act or an instance of going under water, as of a submarine or a skin diver.
• noun A nearly vertical descent at an accelerated speed through the air.
• noun A rapid or abrupt decrease.
• noun Slang A disreputable or run-down bar or nightclub.
• noun A run-down residence.
• noun A knockout feigned by a prizefighter.
• noun An exaggerated fall, especially by a hockey player, intended to draw a penalty against an opponent.
• noun A lunge or a headlong jump.
• noun Football An offensive play in which the carrier of the ball plunges into the opposing line in order to gain short yardage.

from The Century Dictionary.

• To descend or plunge head first into water; thrust the body suddenly into water or other fluid; plunge deeply: as, to dive for shells.
• To make a plunge in any way; plunge suddenly downward or forward, especially so as to disappear: as, to dive down a precipice or into a forest.
• To plunge or enter deeply into something that engrosses the attention; engage deeply in anything: as, to dive to the bottom of a subject; to dive into the whirl of business.
• To explore by diving.
• noun A descent or plunge head first into water or other fluid; a “header”: as, a dive from a spring-board.
• noun A sudden attack or swoop: as, to make a dive.
• noun A disreputable place of resort, where drinking and other forms of vice are indulged in, and, commonly, vulgar entertainments are given: so called because often situated in basements or other half-concealed places into which the resorters may “dive” with little risk of observation.

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

• noun A plunge headforemost into water, the act of one who dives, literally or figuratively.
• noun Slang A place of low resort.
• transitive verb obsolete To plunge (a person or thing) into water; to dip; to duck.
• transitive verb rare To explore by diving; to plunge into.
• intransitive verb To plunge into water head foremost; to thrust the body under, or deeply into, water or other fluid.
• intransitive verb Fig.: To plunge or to go deeply into any subject, question, business, etc.; to penetrate; to explore.

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

• noun Plural form of diva.