Noun

(uncountable) The quality of being different.

(countable) A characteristic of something that makes it different from something else.

* {{quote-magazine, title=Towards the end of poverty

, date=2013-06-01, volume=407, issue=8838, page=11, magazine=(The Economist) citation , passage=But poverty’s scourge is fiercest below $1.25 (the average of the 15 poorest countries’ own poverty lines, measured in 2005 dollars and adjusted for differences in purchasing power): people below that level live lives that are poor, nasty, brutish and short.}}

(countable) A disagreement or argument.

We have our little differences , but we are firm friends.

* Shakespeare

What was the difference ? It was a contention in public.

* T. Ellwood

Away therefore went I with the constable, leaving the old warden and the young constable to compose their difference as they could.

(countable, uncountable) Significant change in or effect on a situation or state.

* 1908 , (Kenneth Grahame), (The Wind in the Willows)

The line of the horizon was clear and hard against the sky, and in one particular quarter it showed black against a silvery climbing phosphorescence that grew and grew. At last, over the rim of the waiting earth the moon lifted with slow majesty till it swung clear of the horizon and rode off, free of moorings; and once more they began to see surfaces—meadows wide-spread, and quiet gardens, and the river itself from bank to bank, all softly disclosed, all washed clean of mystery and terror, all radiant again as by day, but with a difference that was tremendous.

(countable) The result of a subtraction; sometimes the absolute value of this result.

(obsolete) Choice; preference.

* Spenser

That now be chooseth with vile difference / To be a beast, and lack intelligence.

(heraldry) An addition to a coat of arms to distinguish two people's bearings which would otherwise be the same. See augmentation and cadency.

(logic) The quality or attribute which is added to those of the genus to constitute a species; a differentia.

(logic circuits) A Boolean operation which is TRUE when the two input variables are different but is otherwise FALSE; the XOR operation ($\backslash scriptstyle\; A\; \backslash overline\; B\; +\; \backslash overline\; A\; B$).

(relational algebra) the set of elements that are in one set but not another ($\backslash scriptstyle\; A\; \backslash overline\; B$).

Noun

(en noun)

The action of opposing or of being in conflict.

An opposite or contrasting position.

An opponent in some form of competition.

* {{quote-magazine, date=2013-08-10, volume=408, issue=8848, magazine=(The Economist)

, title= Can China clean up fast enough? , passage=That worries the government, which fears that environmental activism could become the foundation for more general political opposition .}}

(astronomy) The apparent relative position of two celestial bodies when one is at an angle of 180 degrees from the other as seen from the Earth.

(senseid)(politics) A political party or movement opposed to the party or government in power.

(legal) In United States intellectual property law, a proceeding in which an interested party seeks to prevent the registration of a trademark or patent.

(chess) A position in which the player on the move must yield with his king allowing his opponent to advance with his own king.