vegetation

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

• noun The plants of an area or a region; plant life.
• noun The act or process of vegetating.
• noun Medicine An abnormal growth on a body part.

from The Century Dictionary.

• noun In phytogeography, the sum total, or a local aggregate, of plant individuals, often of many species, viewed with reference to their ecological adjustment to each other and to all the efficient factors of their environment: contrasted with flora, which denotes a scheme of species rather than a sum of individuals.
• noun The act or process of vegetating; the process of growing exhibited by plants.
• noun Plants collectively: as, luxuriant vegetation.
• noun In pathology, an excrescence or growth on any surface of the body.

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

• noun The act or process of vegetating, or growing as a plant does; vegetable growth.
• noun The sum of vegetable life; vegetables or plants in general.
• noun (Med.) An exuberant morbid outgrowth upon any part, especially upon the valves of the heart.
• noun (Old Chem.) a crystalline growth of an arborescent form.

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

• noun uncountable Plants, taken collectively.
• noun pathology, countable An abnormal verrucous or fibrinous growth

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

• noun all the plant life in a particular region or period
• noun an abnormal growth or excrescence (especially a warty excrescence on the valves of the heart)
• noun inactivity that is passive and monotonous, comparable to the inactivity of plant life
• noun the process of growth in plants