Noun

(en noun)

A drawing showing technical details of a building, machine, etc., with unwanted details omitted, and often using symbols rather than detailed drawing to represent doors, valves, etc.

The plans for many important buildings were once publicly available.

A set of intended actions, usually mutually related, through which one expects to achieve a goal.

He didn't really have a plan ; he had a goal and a habit of control.

A two-dimensional drawing of a building as seen from above with obscuring or irrelevant details such as roof removed, or of a floor of a building, revealing the internal layout; as distinct from the elevation.

Seen in plan , the building had numerous passageways not apparent to visitors.

A method; a way of procedure; a custom.

* Wordsworth

The simple plan , / That they should take who have the power, / And they should keep who can.

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 ($\backslash scriptstyle\; A\; \backslash overline\; B$).