and omissions between sentences (using a period and a space followed by three dots: . ...). The Chicago Style Q&A recommends that writers avoid using the precomposed … (U+2026) character in manuscripts and to place three periods plus two nonbreaking spaces (. . .) instead, leaving the editor, publisher, or typographer to replace them later.The Modern Language Association (MLA) used to indicate that an ellipsis must include spaces before and after each dot in all uses. If an ellipsis is meant to represent an omission, square brackets must surround the ellipsis to make it clear that there was no pause in the original quote: [ . . . ]. Currently, the MLA has removed the requirement of brackets in its style handbooks. However, some maintain that the use of brackets is still correct because it clears confusion.The MLA now indicates that a three-dot, spaced ellipsis  . . . should be used for removing material from within one sentence within a quote. When crossing sentences (when the omitted text contains a period, so that omitting the end of a sentence counts), a four-dot, spaced (except for before the first dot) ellipsis . . . . should be used. When ellipsis points are used in the original text, ellipsis points that are not in the original text should be distinguished by enclosing them in square brackets (e.g. text [...] text).According to the Associated Press, the ellipsis should be used to condense quotations.
(Gabriele D’Annunzio, Il piacere)

Usage in computer system menus
In computer menu functions or buttons, an ellipsis means that upon selection more options (sometimes in the form of a dialog box) will be displayed, where the user can or must make a choice. If the ellipsis is absent, the function is immediately executed upon selection. For example, the menu item "Save" indicates that the file will be overwritten without further input, whereas "Save as..." indicates that a dialog follows where the user can, for example, select another location, file name, or format. Ellipses are also used as a separate button (particularly considering the limited screen area of mobile apps) to represent partially or completely hidden options. This usage may alternatively be described as a "More button" (see also hamburger button signifying completely hidden options). In mobile, web, and general application design, the vertical ellipsis, ⋮, is sometimes used as an interface element, where it is sometimes called a kebab icon. The element typically indicates that a navigation menu can be accessed when the element is activated, and is a smaller version of the hamburger icon (≡) which is a stylized rendering of a menu. In mathematical notation
An ellipsis is also often used in mathematics to mean "and so forth".