Didot point (dp) is a unit of typography and typesetting. In "dot", the size of the font, ascenders and descenders, and the spacing between lines of text are specified. The unit originates from classical typesetting technology and has been adopted, slightly modified, in electronic typesetting technology.
One Didot point (1dp) corresponds to 1/2660 m or 0.3759 mm. 1 mm is therefore 2.66 dp. In electronic typesetting, the "dot" is based on the inch and is abbreviated as "pt" or "bp". One point (1pt) is equal to 1/72 inch or 0.3527 mm. 1 mm is therefore 2.835 pt.
In addition to the unit didot point, classical typesetting also used the cicero, which is equivalent to 12 didot points. The cicero is not used in electronic typesetting.
In addition, the English unit of measurement pica is also used, which is also used for the type width. One pica corresponds to 12 pica points, 1/6 inch or 0.351 mm.
Another unit used in typesetting, based on the didot point, is the twip (twentieth of a point). A twip is equal to 1/20 Didot point, 1/1440th (72 x 20) of an inch, or 1/567th of a centimeter.