A twip is a typographical

Typography

Typography is the art and technique of arranging type in order to make language visible. The arrangement of type involves the selection of typefaces, point size, line length, leading , adjusting the spaces between groups of letters and adjusting the space between pairs of letters...

 measurement, defined as 1/20 of a typographical point

Point (typography)

In typography, a point is the smallest unit of measure, being a subdivision of the larger pica. It is commonly abbreviated as pt. The point has long been the usual unit for measuring font size and leading and other minute items on a printed page....

. One twip is 1/1440 inch or 17.639 µm when derived from the PostScript

PostScript

PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...

 point at 72 to the inch, and 1/1445.4 inch or 17.573 µm based on the printer's point at 72.27 to the inch.

In micro-blogging

• to "twip" is the process of reducing a larger comment, post, or blog to the micro-blog limit of 140 characters.

In computing

Twips are screen-independent units to ensure that the proportion of screen elements are the same on all display systems. A twip is defined as being 1/1440 of an inch.

A Pixel is a screen-dependent unit, standing for 'picture element'. A pixel is a dot that represents the smallest graphical measurement on a screen.
Twips are the default unit of measurement in Visual Basic

Visual Basic

Visual Basic is the third-generation event-driven programming language and integrated development environment from Microsoft for its COM programming model...

 (version 6 and earlier, prior to VB.NET). Converting between twips and screen pixels is achieved using functions such as TwipsPerPixelX and TwipsPerPixelY.

Twips are a commonly used unit with Symbian OS

Symbian

Symbian is a mobile operating system and computing platform designed for smartphones and currently maintained by Accenture. The Symbian platform is the successor to Symbian OS and Nokia Series 60; unlike Symbian OS, which needed an additional user interface system, Symbian includes a user...

 bitmap images and are also used internally in SWF

SWF

SWF is an Adobe Flash file format used for multimedia, vector graphics and ActionScript. Originating with FutureWave Software, then transferred to Macromedia, and then coming under the control of Adobe, SWF files can contain animations or applets of varying degrees of interactivity and function.,...

 format. They are also used in Rich Text Format

Rich Text Format

The Rich Text Format is a proprietary document file format with published specification developed by Microsoft Corporation since 1987 for Microsoft products and for cross-platform document interchange....

 from Microsoft for platform-independent exchange and they are the base length unit in LibreOffice

LibreOffice

LibreOffice is a free and open source office suite developed by The Document Foundation as a fork of OpenOffice.org. It is largely compatible with other major office suites, including Microsoft Office, and available on a variety of platforms...

.

Flash internally calculates anything that uses pixels with twips (or 1/20 of a pixel). Sprites, movie clips and any other object on the stage are positioned with twips. As a result, the coordinates of (for example) sprites are always multiples of 0.05 (i.e. 1/20).