# Definition of *diagonal* in English:

## diagonal

Syllabification: di·ag·o·nalPronunciation: /dīˈaɡənl
/

(abbreviation: diag.)

### adjective

1(Of a straight line) joining two opposite corners of a square, rectangle, or other straight-sided shape.

More example sentences

- Draw two diagonal lines dividing the square and the rectangle into triangles.
- One option is to draw a diagonal line between two opposite points to represent movement between here and there.
- The design was very nice, with diagonal lines forming a grid, each square filled with a snapshot of the movie in rich, warm tones.

1.1(Of a line) straight and at an angle; slanting:

*a tie with diagonal stripes*More example sentences

- The film, with the exception of one shot, is composed of precisely two camera angles: a diagonal shot from the dashboard towards the passenger seat, and another, similar shot towards the driver seat.
- Pencil-thin diagonal blues and greens angle across the surface like tracer-bullet tracks streaking across a movie screen.
- Score the squid by holding the knife at an angle and making diagonal cuts, taking care not to cut right through.

**crosswise**, crossways, slanting, slanted, aslant, oblique, angled, at an angle; cater-cornered, kitty-cornered

### noun

Back to top 1A straight line joining two opposite corners of a square, rectangle, or other straight-sided shape.

More example sentences

- Do this at a diagonal, from one corner of the square to the opposite corner.
- For example, the Pythagoreans did not expect to uncover irrational numbers in the diagonal of a square.
- The particular tablet which concerns us is not one relating to administration but one which presents a geometrical problem which asks for the dimensions of a rectangle whose area and diagonal are known.

1.1

*Mathematics*The set of elements of a matrix that lie on a line joining two opposite corners.More example sentences

- The alpha values and the mean interitem correlations are presented in the diagonals of the matrices in Table 2.
- The diagonal of the rate matrix is specified such that the row sums are equal to zero.
- If we restrict ourselves to the 2x2 arrays whose diagonals lie on the main diagonal of the table, then the sum of four numbers in the array is always a perfect square.

1.2A slanting straight pattern or line:

*the bars of light made diagonals across the entrance**tiles can be laid***on the diagonal**More example sentences

- Let stand ten minutes, then slice very thin and on the diagonal.
- Take cuttings from last seasons growth, cut just below the bud and trim the top on the diagonal.
- The paintings are thick with diagonals; light is pure color, color is pure stroke.

1.3

*Chess*A slanting row of squares whose color is the same.More example sentences

- If you move a pawn to open up a diagonal for a bishop, then should you usually NOT move up another pawn to develop the bishop on the other diagonal.
- After a queen pawn opening, Hort threatened mate on the long diagonal.
- As frequently happens in such a situation, White does not have a diagonal for his dark Bishop, nor does he have any other diagonals from which to aim at his opponent's King.

### Origin

mid 16th century: from Latin *diagonalis*, from Greek *diagōnios* 'from angle to angle', from *dia* 'through' + *gōnia* 'angle'.

## Definition of **diagonal** in:

- The British & World English dictionary
- The English Synonyms
- The US English Synonyms
- The Spanish dictionary