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diagonal

/daɪˈægənl/
/daɪˈægənəl/
IPA guide

Other forms: diagonals

A diagonal is made out of a straight line that's set at an angle instead of straight up or across. If you picture a square and draw a line connecting the opposite corners, that’s a diagonal line.

You’ll find diagonal lines in geometry, and also in the world around you. A quarterback might throw a diagonal pass that angles across the field, or you might buy a snazzy new leotard with diagonal stripes. Diagonal can be either a noun or an adjective. You could call the steep slope of a hill a diagonal across the sky, or you could talk about the diagonal hillside reaching up toward the clouds.

Definitions of diagonal
  1. adjective
    having an oblique or slanted direction
    inclined
    at an angle to the horizontal or vertical position
  2. adjective
    connecting two nonadjacent corners of a plane figure or any two corners of a solid that are not in the same face
    “a diagonal line across the page”
    synonyms:
    oblique
    slanting or inclined in direction or course or position--neither parallel nor perpendicular nor right-angled
  3. noun
    (geometry) a straight line connecting any two vertices of a polygon that are not adjacent
    see moresee less
    type of:
    straight line
    a line traced by a point traveling in a constant direction; a line of zero curvature
  4. noun
    a line or cut across a fabric that is not at right angles to a side of the fabric
    synonyms: bias
    see moresee less
    type of:
    straight line
    a line traced by a point traveling in a constant direction; a line of zero curvature
  5. noun
    (mathematics) a set of entries in a square matrix running diagonally either from the upper left to lower right entry or running from the upper right to lower left entry
    see moresee less
    type of:
    set
    (mathematics) an abstract collection of numbers or symbols
  6. noun
    an oblique line of squares of the same color on a checkerboard
    “the bishop moves on the diagonals
    see moresee less
    types:
    main diagonal, principal diagonal
    the diagonal of a square matrix running from the upper left entry to the lower right entry
    secondary diagonal
    the diagonal of a square matrix running from the lower left entry to the upper right entry
    type of:
    line
    a formation of people or things one behind another
    line
    a formation of people or things one beside another
  7. noun
    a punctuation mark (/) used to separate related items of information such as words, lines of text, or numbers
    see moresee less
    type of:
    punctuation, punctuation mark
    the marks used to clarify meaning by indicating separation of words into sentences and clauses and phrases
Pronunciation
US
/daɪˈægənl/
UK
/daɪˈægənəl/
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DISCLAIMER: These example sentences appear in various news sources and books to reflect the usage of the word ‘diagonal'. Views expressed in the examples do not represent the opinion of Vocabulary.com or its editors. Send us feedback
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