# Skew

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The term **skew**, generally referring to some difference from an expected or optimal value, is common in both telecommunications and mathematics.

## Telecommunication

- In parallel transmission, the difference in arrival time of bits transmitted at the same time.

- For data recorded on multichannel magnetic tape, the difference between reading times of bits recorded in a single transverse line.

*Note:* Skew is usually interpreted to mean the difference in reading times between bits recorded on the tracks at the extremities, or edges, of the tape.

- In facsimile systems, the angular deviation of the received frame from rectangularity caused by asynchronism between the scanner and the recorder.

*Note:* Skew is expressed numerically as the tangent of the deviation angle.

- In facsimile, the angle between the scanning line, or recording line, and the perpendicular to the paper path.

- File:Skew 1 degree.png
*Example of +1 degree (counter-clockwise) skew in a facsimile image. The red line is perfectly horizontal.*

*Source*: from Federal Standard 1037C and from MIL-STD-188

## Mathematics

- In statistics, skew can refer to the skewness of a distribution.
- In linear algebra, a skew-symmetric matrix is a matrix which is the negative of its own transpose.
- In geometry, skew lines are lines which do not intersect yet are not parallel.