difference

Less common meanings

5. 5
   set theorynouncountable or uncountable

   The set of elements that belong to one set but not to another.

   The difference of A and B includes every member of A that is absent from B.

   Computing the difference of two sets leaves out their shared elements.

   Note

   Mathematics and relational algebra use it for what remains when one set is taken away from another. Written AB̄, it means everything in A that is not also in B. As with subtraction, order matters: the difference of A and B and the difference of B and A share no elements at all. Read it as "A minus B" and its kinship with arithmetic subtraction is plain. Source

   Checked 31 Oct 2026 · 6 facts

   • Set difference contains the elements of the first set that are absent from the second. wiki.math.ntnu.no
   • Relational algebra uses the same operation on compatible relations. cs.rpi.edu
   • AB̄ denotes A intersected with the complement of B when juxtaposition denotes intersection. wileyindia.com
   • Set difference is not commutative. ww2.coastal.edu
   • The opposite differences are disjoint: by the cited definition, a common element would have to be both in A and outside A. mathstats-materials.uncg.edu
   • Set difference can be read as A minus B and described as subtraction. cs.utexas.edu
6. 6
   species trait (logic)nouncountable or uncountable

   The quality or attribute added to those of a genus to mark off a species; a differentia.

   Philosophers held that the difference of the human species is the capacity to reason.

   To define a species, one adds its difference to the broader genus.

   Note

   Logic's term for what separates a species from the rest of its genus. English holds two forms of one Latin word here. "Difference" arrived through Old French, while "differentia" kept its Latin shape, so the two are doublets. In logic they mean exactly the same thing. A definition in this tradition takes the form genus plus difference. Source

   Checked 31 Oct 2026 · 5 facts

   • In traditional logic, a difference distinguishes a species from others within its genus. gutenberg.org
   • Difference entered English through Old French and derives from Latin differentia. en.wiktionary.org
   • Differentia retains the Latin form, and difference and differentia are etymological doublets. en.wiktionary.org
   • Difference and differentia are synonymous in the specified logical sense. gutenberg.org
   • Traditional logical definition combines genus and difference. gutenberg.org
7. 7
   nounobsoletecountable or uncountable

   Choice or preference; the inclination to favor one thing over another.

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

   1590, Edmund Spenser, The Faerie Queene

   Note

   Spenser could still use the word for a choice between things, a meaning now obsolete. In The Faerie Queene (1590), someone "chooseth with vile difference / To be a beast", which means he makes a base preference. Modern readers easily take the word as "distinction" and misread the line. The sense belongs to reading older verse. In new writing, "choice" or "preference" says it plainly. Source

   Checked 31 Oct 2026 · 3 facts

   • Spenser used difference to mean choice or preference. en.wiktionary.org
   • The Faerie Queene, including Book II, was first published in 1590. en.wikisource.org
   • The quoted words occur in the poem; Guyon speaks them about Gryll's preference for being a beast. en.wikisource.org
8. 8
   verbobsoletetransitive

   To distinguish or set apart one thing from another.

   This simple spectation of the lungs is differenced from that which concomitates a pleurisy.

   1672, Gideon Harvey, Morbus Anglicus

   Note

   The verb is regular (differences, differencing, differenced) and obsolete in ordinary English. Gideon Harvey in Morbus Anglicus (1666) uses it to tell one lung complaint from another. Heraldry kept it much longer: Arthur Charles Fox-Davies's The Art of Heraldry (1904) describes arms "differenced by the addition of a canton". Outside that field, "distinguish" or "differentiate" is the safe choice. Source

   Checked 31 Oct 2026 · 5 facts

   • The verb has the regular forms differences, differencing, and differenced. en.wiktionary.org
   • Morbus Anglicus was first published in 1666; 1672 is its second edition. en.wikisource.org
   • Harvey uses differenced to distinguish a lung condition from one accompanying pleurisy. en.wiktionary.org
   • Arthur Charles Fox-Davies wrote The Art of Heraldry, published in 1904. en.wikipedia.org
   • The book describes arms using the quoted phrase. archive.org
9. 9
   nounrare

   A Boolean operation that is true when its two inputs differ and false otherwise; the XOR operation.
10. 10
    noun

    An addition to a coat of arms that distinguishes the bearings of two people which would otherwise be identical.