propagation

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

• noun Multiplication or increase, as by natural reproduction.
• noun The process of spreading to a larger area or greater number; dissemination.
• noun Physics The act or process of propagating, especially the process by which a disturbance, such as the motion of electromagnetic or sound waves, is transmitted through a medium such as air or water.

from The Century Dictionary.

• noun The act of propagating; the multiplication or continuance of the kind or species by natural generation or reproduction: as, the propagation of plants or animals.
• noun The spreading or extension of anything; diffusion: as, the propagation of Christianity; the propagation of socialistic ideas.
• noun Increase; augmentation; enlargement; aggrandizement.
• noun Transmission from one point to another, as of sound by waves of condensation and rarefaction in the air, and of radiant heat and light by undulations in the ether. See sound, heat, light, and radiant energy (under energy).
• noun Synonyms Increase, generation, procreation, breeding.
• noun Dissemination.

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

• noun The act of propagating; continuance or multiplication of the kind by generation or successive production.
• noun The spreading abroad, or extension, of anything; diffusion; dissemination

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

• noun the multiplication or natural increase in a population
• noun the dissemination of something to a larger area or greater number
• noun physics the act of propagating, especially the movement of a wave
• noun genetics the elongation part of transcription
• noun religion winning new converts
• noun some degree of success in the spread of propaganda

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

• noun the movement of a wave through a medium
• noun the spreading of something (a belief or practice) into new regions
• noun the act of producing offspring or multiplying by such production