interference

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

• noun The act or an instance of hindering, obstructing, or impeding.
• noun Something that hinders, obstructs, or impedes.
• noun Sports Illegal obstruction or hindrance of an opposing player, such as hindrance of a receiver by a defender in football, hindrance of a fielder by a base runner in baseball, or checking a player not in possession of the puck in ice hockey.
• noun Football The legal blocking of defensive tacklers to protect and make way for the ball carrier.
• noun Physics The variation of wave amplitude that occurs from the superposition of two or more waves.
• noun The inhibition or prevention of clear reception of broadcast signals.
• noun The distorted portion of a received signal.
• noun The negative or distorting effect that new learning can have on previous learning or that previous learning can have on new learning.

from The Century Dictionary.

• noun The act of interfering; interposition; especially, intermeddling.
• noun A clashing or collision; the act of coming into violent contact.
• noun In farriery, a striking of one foot against the one next to it, as one hind foot against the other.
• noun In Amer. patent law, the conflict between two patents or applications for patent which claim in whole or in part the same invention.
• noun In physics, the mutual action of waves of any kind (whether those in water, or sound-, heat-, or light-waves) upon one another, by which, under certain conditions, the vibrations and their effects are increased, diminished, or neutralized.
• noun In base-ball and foot-ball, the act of interfering. See interfere, v. i., 5 and 6.

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

• noun The act or state of interfering
• noun (Physics) The mutual influence, under certain conditions, as from streams of light, or pulsations of sound, or, generally, two waves or vibrations of any kind, producing certain characteristic phenomena, as colored fringes, dark bands, or darkness, in the case of light, silence or increased intensity in sounds; neutralization or superposition of waves generally.
• noun (Patent Law) The act or state of interfering, or of claiming a right to the same invention.
• noun (Optics) the figures observed when certain sections of crystallized bodies are viewed in converging polarized light; thus, a section of a uniaxial crystal, cut normal to the vertical axis, shows a series of concentric colored rings with a single black cross; -- so called because produced by the interference of luminous waves.
• noun (Optics) See Fringe.

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

• noun The act of interfering with something, or something that interferes.
• noun sports The illegal obstruction of an opponent in some ball games.
• noun physics An effect caused by the superposition of two systems of waves, such as a distortion on a broadcast signal due to atmospheric or other effects.
• noun US, law In United States patent law, an inter partes proceeding to determine the priority issues of multiple patent applications; a priority contest.

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

• noun (American football) blocking a player's path with your body
• noun electrical or acoustic activity that can disturb communication
• noun the act of hindering or obstructing or impeding
• noun a policy of intervening in the affairs of other countries
• noun any obstruction that impedes or is burdensome