influence

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

• noun A power affecting a person, thing, or course of events, especially one that operates without any direct or apparent effort.
• noun Power to sway or affect based on prestige, wealth, ability, or position.
• noun A person who exerts such power.
• noun A determining factor believed by some to affect individual tendencies and characteristics understood to be caused by the positions of the stars and planets at the time of one's birth.
• noun Factors believed to be caused by the changing positions of the stars and planets in relation to their positions at the time of one's birth.
• transitive verb To have an influence on (something); change.
• transitive verb To change the behavior or thinking of (someone); sway.
• idiom (under the influence) Intoxicated, especially with alcohol.

from The Century Dictionary.

• To exercise influence on; modify, affect, or sway, especially by intangible or invisible means; act on or affect by the transmission of some energy or potency: as, the sun influences the tides; to influence a person by the hope of reward or the fear of punishment.
• Synonyms To lead, induce, move, impel, actuate, prevail upon.
• noun A flowing in; direct influx of energy: followed by into.
• noun In astrology, the radiation of power from the stars in certain positions and collocations, affecting human actions and destinies; a supposed positive occult power exerted by the stars over human affairs.
• noun Outgoing energy or potency that produces effects (primarily internal), or affects, modifies, or sways by insensible or invisible means that to which it is directed or on which it operates: sometimes used for the effect produced: as, the influence of heat on vegetation; the influence of climate on character; the influence of the moon on the tides; the influence of example on the young.
• noun Capacity or power for producing effects by insensible or invisible means; authority; power; ascendancy over others; sway: as, a man of influence; a position of great influence.
• noun In electricity and magnetism, same as induction, 6.

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

• transitive verb To control or move by power, physical or moral; to affect by gentle action; to exert an influence upon; to modify, bias, or sway; to affect; to move; to persuade; to induce.
• noun obsolete A flowing in or upon; influx.
• noun Hence, in general, the bringing about of an effect, physical or moral, by a gradual process; controlling power quietly exerted; agency, force, or tendency of any kind which affects, modifies, or sways.
• noun Power or authority arising from elevated station, excelence of character or intellect, wealth, etc.; reputation; acknowledged ascendency.
• noun (Elec.) Induction.

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

• noun The power to affect, control or manipulate something or someone; the ability to change the development of fluctuating things such as conduct, thoughts or decisions.
• noun An action exerted by a person or thing with such power on another to cause change.
• noun A person or thing exerting such power or action.
• noun astrology An element believed to determine someone's character or individual tendencies, caused by the position of the stars and planets at the time of one's birth.
• noun obsolete The action of flowing in; influx.
• noun electricity electrostatic induction.
• verb transitive To affect by gentle action; to exert an influence upon; to modify, bias, or sway; to persuade or induce.
• verb intransitive To exert, make use of one's influence.
• verb transitive, obsolete To cause to flow in or into; infuse; instill.

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

• noun the effect of one thing (or person) on another
• noun a cognitive factor that tends to have an effect on what you do
• noun a power to affect persons or events especially power based on prestige etc
• verb have and exert influence or effect
• verb induce into action by using one's charm
• noun one having power to influence another
• verb shape or influence; give direction to
• noun causing something without any direct or apparent effort